0% found this document useful (0 votes)

70 views52 pages

18bit SAR - TI

18 bit SAR

Uploaded by

nsitdelhi

We take content rights seriously. If you suspect this is your content, claim it here.

Available Formats

Download as PDF, TXT or read online on Scribd

0% found this document useful (0 votes)

70 views52 pages

18bit SAR - TI

18 bit SAR

Uploaded by

nsitdelhi

We take content rights seriously. If you suspect this is your content, claim it here.

Available Formats

Download as PDF, TXT or read online on Scribd

You are on page 1/ 52

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

18-Bit, 400-kSPS, Serial Interface, microPower, Miniature,

True-Differential Input, SAR Analog-to-Digital Converter
Check for Samples: ADS8885

1FEATURES APPLICATIONS
• Sample Rate: 400 kHz
234 • Automatic Test Equipment (ATE)
• No Latency Output • Instrumentation and Process Controls
• Unipolar, True-Differential Input Range: • Precision Medical Equipment
–VREF to +VREF • Low-Power, Battery-Operated Instruments
• Wide Common-Mode Voltage Range:
0 V to VREF with 90-dB CMRR (min) DESCRIPTION
• SPI™-Compatible Serial Interface with The ADS8885 is an 18-bit, 400-kSPS, true-differential
Daisy-Chain Option input, analog-to-digital converter (ADC). The device
operates with a 2.5-V to 5-V external reference,
• Excellent AC and DC Performance:
offering a wide selection of signal ranges without
– SNR: 100 dB, THD: –115 dB additional input signal scaling. The reference voltage
– INL: ±1.5 LSB (typ), ±3.0 LSB (max) setting is independent of, and can exceed, the analog
– DNL: +1.5 and –1 LSB (max), 18-Bit NMC supply voltage (AVDD).
• Wide Operating Range: The device offers an SPI-compatible serial interface
that also supports daisy-chain operation for
– AVDD: 2.7 V to 3.6 V
cascading multiple devices. An optional busy-
– DVDD: 1.65 V to 3.6 V indicator bit makes synchronizing with the digital host
(Independent of AVDD) easy.
– REF: 2.5 V to 5 V (Independent of AVDD) The device supports unipolar, true-differential analog
– Operating Temperature: –40°C to +85°C input signals with a differential input swing of –VREF to
• Low-Power Dissipation: +VREF. This true-differential analog input structure
allows for a common-mode voltage of any value in
– 2.6 mW at 400 kSPS the range of 0 V to +VREF (when both inputs are
– 0.65 mW at 100 kSPS within the operating input range of –0.1 V to VREF
– 65 µW at 10 kSPS + 0.1 V).
• Power-Down Current (AVDD): 50 nA Device operation is optimized for very low-power
• Full-Scale Step Settling to 18 Bits: 1200 ns operation. Power consumption directly scales with
speed. This feature makes the ADS8885 excellent for
• Packages: MSOP-10 and SON-10 lower-speed applications.
2.5 V to 5 V 2.7 V to 3.6 V
VDIFF True-Differential Input Range
Traditional Input Range

ADS8885 Input Range +VREF REF AVDD

1.65 V to 3.6 V
0 V - VREF DVDD
VREF
AINP
DIN
VCM VCM ADS8885 SCLK
0V VREF
DOUT
0V AINM
0 V - VREF CONVST
VREF/2
GND
-VREF

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
2 TINA is a trademark of Texas Instruments Inc..
3 SPI is a trademark of Motorola Inc.
4 All other trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date. Copyright © 2013, Texas Instruments Incorporated
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.

FAMILY INFORMATION (1)

THROUGHPUT 18-BIT, TRUE-DIFFERENTIAL 16-BIT, SINGLE-ENDED 16-BIT, TRUE-DIFFERENTIAL
100 kSPS ADS8887 ADS8866 ADS8867
250 kSPS — — —
400 kSPS ADS8885 ADS8864 ADS8865
500 kSPS — ADS8319 (2) ADS8318 (2)
680 kSPS ADS8883 ADS8862 ADS8863
1 MSPS ADS8881 ADS8860 ADS8861

(1) For the most current package and ordering information, see the Package Option Addendum at the end of this document, or visit the
device product folder at www.ti.com.
(2) Pin-to-pin compatible device with AVDD = 5 V.

ABSOLUTE MAXIMUM RATINGS (1)

Over operating free-air temperature range, unless otherwise noted.
VALUE
MIN MAX UNIT
AINP to GND or AINN to GND –0.3 REF + 0.3 V
AVDD to GND or DVDD to GND –0.3 4 V
REF to GND –0.3 5.7 V
Digital input voltage to GND –0.3 DVDD + 0.3 V
Digital output to GND –0.3 DVDD + 0.3 V
Operating temperature range, TA –40 +85 °C
Storage temperature range, Tstg –65 +150 °C

(1) Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under electrical characteristics is not
implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

THERMAL INFORMATION
ADS8885
(1)
THERMAL METRIC DGS DRC UNITS
10 PINS 10 PINS
θJA Junction-to-ambient thermal resistance 151.9 111.1
θJCtop Junction-to-case (top) thermal resistance 45.4 46.4
θJB Junction-to-board thermal resistance 72.2 45.9
°C/W
ψJT Junction-to-top characterization parameter 3.3 3.5
ψJB Junction-to-board characterization parameter 70.9 45.5
θJCbot Junction-to-case (bottom) thermal resistance N/A N/A

(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.

2 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

ELECTRICAL CHARACTERISTICS
All minimum and maximum specifications are at TA = –40°C to +85°C, AVDD = 3 V, DVDD = 3 V, VREF = 5 V,
VCM = VREF / 2 V, and fSAMPLE = 400 kSPS, unless otherwise noted.
Typical specifications are at TA = +25°C, AVDD = 3 V, and DVDD = 3 V.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
ANALOG INPUT
Full-scale input span (1) (2) AINP – AINN –VREF VREF V

(1) (2)
AINP –0.1 VREF + 0.1 V
Operating input range
AINN –0.1 VREF + 0.1 V
VCM Input common-mode range 0 VREF / 2 VREF V
CI Input capacitance AINP and AINN terminal to GND 59 pF
Input leakage current During acquisition for dc input 5 nA
SYSTEM PERFORMANCE
Resolution 18 Bits
NMC No missing codes 18 Bits
DNL Differential linearity –0.99 ±0.7 1.5 LSB (3)
INL Integral linearity (4) –3 ±1.5 3 LSB (3)
(5)
EO Offset error –4 ±1 4 mV
Offset error drift with temperature ±1.5 µV/°C
EG Gain error –0.01 ±0.005 0.01 %FSR
Gain error drift with temperature ±0.15 ppm/°C
CMRR Common-mode rejection ratio With common-mode input signal = 5 VPP at dc 90 100 dB
PSRR Power-supply rejection ratio At mid-code 80 dB
Transition noise 0.7 LSB
SAMPLING DYNAMICS
tconv Conversion time 500 1300 ns
tACQ Acquisition time 1200 ns
Maximum throughput rate
400 kHz
with or without latency
Aperture delay 4 ns
Aperture jitter, RMS 5 ps
Step response Settling to 18-bit accuracy 1200 ns
Overvoltage recovery Settling to 18-bit accuracy 1200 ns

(1) Ideal input span, does not include gain or offset error.
(2) Specified for VCM = VREF / 2. Refer to the Analog Input section for the effect of VCM on the full-scale input range.
(3) LSB = least significant bit.
(4) This parameter is the endpoint INL, not best-fit.
(5) Measured relative to actual measured reference.

Copyright © 2013, Texas Instruments Incorporated Submit Documentation Feedback 3

Product Folder Links: ADS8885
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

ELECTRICAL CHARACTERISTICS (continued)

All minimum and maximum specifications are at TA = –40°C to +85°C, AVDD = 3 V, DVDD = 3 V, VREF = 5 V,
VCM = VREF / 2 V, and fSAMPLE = 400 kSPS, unless otherwise noted.
Typical specifications are at TA = +25°C, AVDD = 3 V, and DVDD = 3 V.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
DYNAMIC CHARACTERISTICS
At 1 kHz, VREF = 5 V 98 99.9 dB
SINAD Signal-to-noise + distortion (6) At 10 kHz, VREF = 5 V 98.7 dB
At 100 kHz, VREF = 5 V 93.3 dB
At 1 kHz, VREF = 5 V 98.5 100 dB
SNR Signal-to-noise ratio (6) At 10 kHz, VREF = 5 V 99.5 dB
At 100 kHz, VREF = 5 V 93.5 dB
At 1 kHz, VREF = 5 V –115 dB
THD Total harmonic distortion (6) (7) At 10 kHz, VREF = 5 V –112 dB
At , VREF = 5 V –102 dB
At 1 kHz, VREF = 5 V 115 dB
SFDR Spurious-free dynamic range (6) At 10 kHz, VREF = 5 V 112 dB
At 100 kHz, VREF = 5 V 102 dB
BW–3dB –3-dB small-signal bandwidth 30 MHz
EXTERNAL REFERENCE INPUT
VREF Input range 2.5 5 V
Reference input current During conversion, 400-kHz sample rate, mid-code 100 μA
Reference leakage current 250 nA
Decoupling capacitor at the REF
CREF 10 22 µF
input
POWER-SUPPLY REQUIREMENTS

Power-supply AVDD Analog supply 2.7 3 3.6 V

voltage DVDD Digital supply range 1.65 1.8 3.6 V
Supply current AVDD 400-kHz sample rate, AVDD = 3 V 0.85 1.2 mA
400-kHz sample rate, AVDD = 3 V 2.6 3.6 mW
PVA Power dissipation 100-kHz sample rate, AVDD = 3 V 0.65 mW
10-kHz sample rate, AVDD = 3 V 65 μW
IAPD Device power-down current (8) 50 nA
DIGITAL INPUTS: LOGIC FAMILY (CMOS)
1.65 V < DVDD < 2.3 V 0.8 × DVDD DVDD + 0.3 V
VIH High-level input voltage
2.3 V < DVDD < 3.6 V 0.7 × DVDD DVDD + 0.3 V
1.65 V < DVDD < 2.3 V –0.3 0.2 × DVDD V
VIL Low-level input voltage
2.3 V < DVDD < 3.6 V –0.3 0.3 × DVDD V
ILK Digital input leakage current ±10 ±100 nA
DIGITAL OUTPUTS: LOGIC FAMILY (CMOS)
VOH High-level output voltage IO = 500-μA source, CLOAD = 20 pF 0.8 × DVDD DVDD V
VOL Low-level output voltage IO = 500-μA sink, CLOAD = 20 pF 0 0.2 × DVDD V
TEMPERATURE RANGE
TA Operating free-air temperature –40 +85 °C

(6) All specifications expressed in decibels (dB) refer to the full-scale input (FSR) and are tested with an input signal 0.5 dB below full-scale,
unless otherwise specified.
(7) Calculated on the first nine harmonics of the input frequency.
(8) The device automatically enters a power-down state at the end of every conversion, and remains in power-down during the acquisition
phase.

4 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

TIMING CHARACTERISTICS

3-WIRE OPERATION
1/fsample
DIN = HIGH
tconv-max tACQ
tclkh
th-CK-DO tclkl
CONVST
tquiet

SCLK 1 2 3 16 17 18
tSCLK
td-CNV-DO
DOUT D17 D16 D15 D2 D1 D0
twh-CNV-min
td-CK-DO td-CK-DOhz

Figure 1. 3-Wire Operation: CONVST Functions as Chip Select

NOTE
Figure 1 shows the timing diagram for the 3-Wire CS Mode Without a Busy Indicator
interface option. However, the timing parameters specified in Table 1 are also applicable
for the 3-Wire CS Mode With a Busy Indicator interface option, unless otherwise specified.
Refer to the Digital Interface section for specific details for each interface option.

Table 1. TIMING REQUIREMENTS: 3-Wire Operation (1)

PARAMETER MIN TYP MAX UNIT
tACQ Acquisition time 1200 ns
tconv Conversion time 500 1300 ns
1/fsample Time between conversions 2500 ns
twh-CNV Pulse duration: CONVST high 10 ns
fSCLK SCLK frequency 16 MHz
tSCLK SCLK period 62.5 ns
tclkl SCLK low time 0.45 0.55 tSCLK
tclkh SCLK high time 0.45 0.55 tSCLK
th-CK-DO SCLK falling edge to current data invalid 3 ns
td-CK-DO SCLK falling edge to next data valid delay 13.4 ns
td-CNV-DO Enable time: CONVST low to MSB valid 12.3 ns
td-CNV-DOhz Disable time: CONVST high or last SCLK falling edge to DOUT 3-state (CS mode) 13.2 ns
tquiet Quiet time 20 ns

(1) All specifications are at TA = –40°C to +85°C, AVDD = 3 V, and DVDD = 3 V, unless otherwise noted.

Copyright © 2013, Texas Instruments Incorporated Submit Documentation Feedback 5

Product Folder Links: ADS8885
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

4-WIRE OPERATION
1/fsample
tconv-max tACQ

CONVST
tsu-DI-CNV twl-CNV
DIN

SCLK 1 2 3 16 17 18

DOUT D17 D16 D15 D2 D1 D0
twh-DI-min
td-DI-DO td-DI-DOhz

Figure 2. 4-Wire Operation: DIN Functions as Chip Select

NOTE
Figure 2 shows the timing diagram for the 4-Wire CS Mode Without a Busy Indicator
interface option. However, the timing parameters specified in Table 2 are also applicable
for the 4-Wire CS Mode With a Busy Indicator interface option, unless otherwise specified.
Refer to the Digital Interface section for specific details for each interface option.

Table 2. TIMING REQUIREMENTS: 4-Wire Operation (1)

PARAMETER MIN TYP MAX UNIT
tACQ Acquisition time 1200 ns
tconv Conversion time 500 1300 ns
1/fsample Time between conversions 2500 ns
twh-DI Pulse duration: DIN high 10 ns
twl-CNV Pulse width: CONVST low 20 ns
td-DI-DO Delay time: DIN low to MSB valid 12.3 ns
td-DI-DOhz Delay time: DIN high or last SCLK falling edge to DOUT 3-state 13.2 ns
tsu-DI-CNV Setup time: DIN high to CONVST rising edge 7.5 ns
th-DI-CNV Hold time: DIN high from CONVST rising edge (see Figure 63) 0 ns

(1) All specifications are at TA = –40°C to +85°C, AVDD = 3 V, and DVDD = 3 V, unless otherwise noted.

6 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

DAISY-CHAIN OPERATION
1/fsample
tconv-
tACQ
max

CONVST

th-CK-CNV

SCLK 1 2 17 18 19 20 35 36

tsu-CK-CNV tsu-DI-CK
DIN 1 = LOW

DOUT 1,
D17 D16 D1 D0
DIN 2

DOUT 2 D17 D16 D1 D0 D17 D16 D1 D0

Device 2 Data Device 1 Data

Figure 3. Daisy-Chain Operation: Two Devices

NOTE
Figure 3 shows the timing diagram for the Daisy-Chain Mode Without a Busy Indicator
interface option. However, the timing parameters specified in Table 3 are also applicable
for the Daisy-Chain Mode With a Busy Indicator interface option, unless otherwise
specified. Refer to the Digital Interface section for specific details for each interface option.

Table 3. TIMING REQUIREMENTS: Daisy-Chain (1)

PARAMETER MIN TYP MAX UNIT
tACQ Acquisition time 1200 ns
tconv Conversion time 500 1300 ns
1/fsample Time between conversions 2500 ns
tsu-CK-CNV Setup time: SCLK valid to CONVST rising edge 5 ns
th-CK-CNV Hold time: SCLK valid from CONVST rising edge 5 ns
tsu-DI-CNV Setup time: DIN low to CONVST rising edge (see Figure 2) 7.5 ns
th-DI-CNV Hold time: DIN low from CONVST rising edge (see Figure 63) 0 ns
tsu-DI-CK Setup time: DIN valid to SCLK falling edge 1.5 ns

(1) All specifications are at TA = –40°C to +85°C, AVDD = 3 V, and DVDD = 3 V, unless otherwise noted.

Copyright © 2013, Texas Instruments Incorporated Submit Documentation Feedback 7

Product Folder Links: ADS8885
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

EQUIVALENT CIRCUITS

500 µA IOL

DOUT 1.4 V

20 pF

500 µA IOH

Figure 4. Load Circuit for Digital Interface Timing

DIN VIH
CONVST VIL
SCLK

VOH VOH
SDO
VOL VOL

Figure 5. Voltage Levels for Timing

8 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

PIN CONFIGURATIONS

DGS PACKAGE
VSSOP-10 DRC PACKAGE
(TOP VIEW, Not to Scale) SON-10
(TOP VIEW, Not to Scale)

REF 1 10 DVDD
REF 1 10 DVDD

AVDD 2 9 DIN
AVDD 2 9 DIN

AINP 3 8 SCLK
AINP 3 Thermal 8 SCLK
PAD
AINN 4 7 DOUT
AINN 4 7 DOUT

GND 5 6 CONVST
GND 5 6 CONVST

PIN ASSIGNMENTS
PIN
PIN NAME NUMBER FUNCTION DESCRIPTION
AINN 4 Analog input Inverting analog signal input
AINP 3 Analog input Noninverting analog signal input
Analog power supply.
AVDD 2 Analog
This pin must be decoupled to GND with a 1-μF capacitor.
Convert input.
CONVST 6 Digital input This pin also functions as the CS input in 3-wire interface mode. Refer to the
Description and Timing Characteristics sections for more details.
Serial data input.
The DIN level at the start of a conversion selects the mode of operation (such as CS
DIN 9 Digital input
or daisy-chain mode). This pin also serves as the CS input in 4-wire interface mode.
Refer to the Description and Timing Characteristics sections for more details.
DOUT 7 Digital output Serial data output
Digital interface power supply.
DVDD 10 Power supply
This pin must be decoupled to GND with a 1-μF capacitor.
Device ground.
Note that this pin is a common ground pin for both the analog power supply (AVDD)
GND 5 Analog, digital
and digital I/O supply (DVDD). The reference return line is also internally connected to
this pin.
Positive reference input.
REF 1 Analog
This pin must be decoupled with a 10-μF or larger capacitor.
Clock input for serial interface.
SCLK 8 Digital input
Data output (on DOUT) are synchronized with this clock.
Exposed thermal pad.
Thermal pad — Thermal pad Texas Instruments recommends connecting the thermal pad to the printed circuit
board (PCB) ground.

Copyright © 2013, Texas Instruments Incorporated Submit Documentation Feedback 9

Product Folder Links: ADS8885
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

TYPICAL CHARACTERISTICS
At TA = +25°C, AVDD = 3 V, DVDD = 3 V, VREF = 5 V, and fSAMPLE = 400 kSPS, unless otherwise noted.

3 1

Typical Differential Nonlinearity (LSB)

AVDD = 3 V AVDD = 3 V
Typical Integral Nonlinearity (LSB)

0.75 REF = 2.5 V

REF = 2.5 V
2 TA = 25C
TA = 25C
0.5
1 0.25

0 0

-0.25
±1
-0.5
±2 -0.75

±3 -1
±131072 131071 ±131072 131071
ADC Output Code C001 ADC Output Code C002

Figure 6. TYPICAL INL (VREF = 2.5 V) Figure 7. TYPICAL DNL (VREF = 2.5 V)

3 1
AVDD = 3 V AVDD = 3 V

Typical Differential Nonlinearity (LSB)

Typical Integral Nonlinearity (LSB)

REF = 5 V 0.75 REF = 5 V

2 TA = 25C
TA = 25C
0.5
1
0.25

0 0

-0.25
±1
-0.5
±2
-0.75

±3 -1
±131072 131071 ±131072 131071
ADC Output Code C003 ADC Output Code C004

Figure 8. TYPICAL INL (VREF = 5 V) Figure 9. TYPICAL DNL (VREF = 5 V)

3 2
AVDD = 3 V AVDD = 3 V
REF = 5 V REF = 5 V
Differential Nonlinearity (LSB)

2 1.5
Integral Nonlinearity (LSB)

1 1

0 0.5

-1 0

-2 -0.5

-3 -1
-40 -15 10 35 60 85 -40 -15 10 35 60 85
Free-Air Temperature (oC) C00 Free-Air Temperature (oC) C00

Figure 10. INL vs TEMPERATURE Figure 11. DNL vs TEMPERATURE

10 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

TYPICAL CHARACTERISTICS (continued)

At TA = +25°C, AVDD = 3 V, DVDD = 3 V, VREF = 5 V, and fSAMPLE = 400 kSPS, unless otherwise noted.
3 2
AVDD = 3 V AVDD = 3 V
TA = 25oC TA = 25oC

Differential Nonlinearity (LSB)

2 1.5
Integral Nonlinearity (LSB)

1 1

0 0.5

-1 0

-2 -0.5

-3 -1
2.5 3 3.5 4 4.5 5 2.5 3 3.5 4 4.5 5
Reference Voltage (V) C00 Reference Voltage (V) C00

Figure 12. INL vs REFERENCE VOLTAGE Figure 13. DNL vs REFERENCE VOLTAGE

40 60
AVDD = 3 V AVDD = 3 V
REF = 2.5 V REF = 5 V
TA = 25oC 50
TA = 25oC
30
Hits per Code (%)

Hits per Code (%)

20 30

20
10
10

0 0
10 12 14 16 18 20 4 6 8 10
ADC Output Code C00 ADC Output Code C01

Figure 14. DC INPUT HISTOGRAM (VREF = 2.5 V) Figure 15. DC INPUT HISTOGRAM (VREF = 5 V)

0 0
-20 AVDD = 3 V ±20 AVDD = 3 V
REF = 2.5 V REF = 5 V
-40 TA = 25C ±40 TA = 25C
fIN = 1 kHz fIN = 1 kHz
-60 ±60
SNR = 95.4 dB SNR = 100 dB
Power (dB)
Power (dB)

-80 THD = ±119 dB ±80 THD = ±115 dB

-100 ±100
-120 ±120
-140 ±140
-160 ±160
-180 ±180
-200 ±200
0 50 100 150 200 0 50 100 150 200
Input Frequency (kHz) C001 Input Frequency (kHz) C002

Figure 16. TYPICAL FFT (VREF = 2.5 V) Figure 17. TYPICAL FFT (VREF = 5 V)

Copyright © 2013, Texas Instruments Incorporated Submit Documentation Feedback 11

Product Folder Links: ADS8885
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

TYPICAL CHARACTERISTICS (continued)

At TA = +25°C, AVDD = 3 V, DVDD = 3 V, VREF = 5 V, and fSAMPLE = 400 kSPS, unless otherwise noted.
102 102

Signal-to-Noise and Distortion (dBFS)

101 101
Signal-to-Noise Ratio (dBFS)

100 100

99 99

98 98

97 97

96 96

95 95
fIN = 1 kHz fIN = 1 kHz
94 94
2.5 3 3.5 4 4.5 5 2.5 3 3.5 4 4.5 5
Reference Voltage (V) C01 Reference Voltage (V) C01

Figure 18. SNR vs REFERENCE VOLTAGE Figure 19. SINAD vs REFERENCE VOLTAGE

18 -109
fIN = 1 kHz fIN = 1 kHz

Total Harmonic Distortion (dBFS)

17.5 -111
Effective Number of Bits

17 -113

16.5 -115

16 -117

15.5 -119

15 -121

14.5 -123

14 -125
2.5 3 3.5 4 4.5 5 2.5 3 3.5 4 4.5 5
Reference Voltage (V) C01 Reference Voltage (V) C01

Figure 20. ENOB vs REFERENCE VOLTAGE Figure 21. THD vs REFERENCE VOLTAGE

126 102
Spurious-Free Dynamic Range (dBFS)

fIN = 1 kHz fIN = 1 kHz

124 101
Signal-to-Noise Ratio (dBFS)

122 100

120 99

118 98

116 97

114 96

112 95

110 94
2.5 3 3.5 4 4.5 5 -40 -15 10 35 60 85
Reference Voltage (V) C01 Free-Air Temperature (oC) C01

Figure 22. SFDR vs REFERENCE VOLTAGE Figure 23. SNR vs TEMPERATURE

12 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

TYPICAL CHARACTERISTICS (continued)

At TA = +25°C, AVDD = 3 V, DVDD = 3 V, VREF = 5 V, and fSAMPLE = 400 kSPS, unless otherwise noted.
102 18
Signal-to-Noise and Distortion (dBFS)

fIN = 1 kHz fIN = 1 kHz

101 17.5

Effective Number of Bits

100 17

99 16.5

98 16

97 15.5

96 15

95 14.5

94 14
-40 -15 10 35 60 85 -40 -15 10 35 60 85
Free-Air Temperature (oC) C01 Free-Air Temperature (oC) C02

Figure 24. SINAD vs TEMPERATURE Figure 25. ENOB vs TEMPERATURE

-109 126

Spurious-Free Dynamic Range (dBFS)

fIN = 1 kHz fIN = 1 kHz
Total Harmonic Distortion (dBFS)

-111 124

-113 122

-115 120

-117 118

-119 116

-121 114

-123 112

-125 110
-40 -15 10 35 60 85 -40 -15 10 35 60 85
Free-Air Temperature (oC) C02 Free-Air Temperature (oC) C02

Figure 26. THD vs TEMPERATURE Figure 27. SFDR vs TEMPERATURE

106 101
Signal-to-Noise and Distortion (dBFS)

104 100
Signal-toNoise Ratio (dBFS)

102 99

100 98

98 97

96 96

94 95

92 94

90 93
0 20 40 60 80 100 0 20 40 60 80 100
Input Frequency (kHz) C02 Input Frequency (kHz) C02

Figure 28. SNR vs INPUT FREQUENCY Figure 29. SINAD vs INPUT FREQUENCY

Copyright © 2013, Texas Instruments Incorporated Submit Documentation Feedback 13

Product Folder Links: ADS8885
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

TYPICAL CHARACTERISTICS (continued)

At TA = +25°C, AVDD = 3 V, DVDD = 3 V, VREF = 5 V, and fSAMPLE = 400 kSPS, unless otherwise noted.
18 -100
17.5

Total Harmonic Distortion (dBFS)

-103
Effective Number of Bits

17 -106
16.5 -109
16 -112
15.5 -115
15 -118
14.5 -121
14 -124
0 20 40 60 80 100 0 20 40 60 80 100
Input Frequency (kHz) C02 Input Frequency (kHz) C02

Figure 30. ENOB vs INPUT FREQUENCY Figure 31. THD vs INPUT FREQUENCY

124 2
Spurious-Free Dynamic Range (dBFS)

121

Analog Supply Current (mA)

1.6
118

115
1.2
112

109 0.8

106
0.4
103

100 0
0 20 40 60 80 100 -40 -15 10 35 60 85
Input Frequency (kHz) C02 Free-Air Temperature (oC) C02

Figure 32. SFDR vs INPUT FREQUENCY Figure 33. SUPPLY CURRENT vs TEMPERATURE

4 1
3.5
Power Consumption (mW))

Analog Supply Current (mA)

0.8
3

2.5
0.6
2

1.5 0.4

1
0.2
0.5

0 0
-40 -15 10 35 60 85 40 100 160 220 280 340 400
Free-Air Temperature (oC) C02 Throughput (kSPS) C03

Figure 34. POWER CONSUMPTION vs TEMPERATURE Figure 35. SUPPLY CURRENT vs THROUGHPUT

14 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

TYPICAL CHARACTERISTICS (continued)

At TA = +25°C, AVDD = 3 V, DVDD = 3 V, VREF = 5 V, and fSAMPLE = 400 kSPS, unless otherwise noted.
3 200

175
2.5
Power Consumption (mW)

Power-Down Current (mA)

150
2
125

1.5 100

75
1
50
0.5
25

0 0
40 100 160 220 280 340 400 -40 -15 10 35 60 85
Throughput (kSPS) C02
C03 Free-Air Temperature (oC) C03

Figure 36. POWER CONSUMPTION vs THROUGHPUT Figure 37. POWER-DOWN CURRENT vs TEMPERATURE

4 0.01

3
0.006
2
Gain Error (%FS)
1
Offset (mV)

0.002
0

-1 -0.002

-2
-0.006
-3

-4 -0.01
-40 -15 10 35 60 85 -40 -15 10 35 60 85
Free-Air Temperature (oC) C03 Free-Air Temperature (oC) C03

Figure 38. OFFSET vs TEMPERATURE Figure 39. GAIN ERROR vs TEMPERATURE

105 18000
AVDD = 3 V
Common-Mode Rejection Ratio (dB)

103 16000
REF = 5 V
101 14000 TA = 25oC
15000 Devices
99 12000
Frequency

97
10000
95
8000
93
6000
91
4000
89
87 2000

85 0
0.001 0.01 0.1 1 10 100 -0.01 -0.005 0 0.005 0.01
Input Frequency (kHz) C03 Gain Error (% FS) C03

Figure 40. CMRR vs INPUT FREQUENCY Figure 41. TYPICAL DISTRIBUTION OF GAIN ERROR

Copyright © 2013, Texas Instruments Incorporated Submit Documentation Feedback 15

Product Folder Links: ADS8885
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

TYPICAL CHARACTERISTICS (continued)

At TA = +25°C, AVDD = 3 V, DVDD = 3 V, VREF = 5 V, and fSAMPLE = 400 kSPS, unless otherwise noted.
8000 16000
AVDD = 3 V AVDD = 3 V
7000 REF = 5 V 14000 REF = 5 V
TA = 25oC TA = 25C
6000 12000 15000 Devices
15000 Devices
5000 10000

Frequency
Frequency

4000 8000

3000 6000

2000 4000

1000 2000

0 0
-4 -3 -2 -1 0 1 2 3 4 ±1.0 ±0.5 0.0 0.5 1.0 1.5
Offset (mV) C03
Differential Nonlinearity Min and Max (LSB) C038

Figure 42. TYPICAL DISTRIBUTION OF OFFSET ERROR Figure 43. TYPICAL DISTRIBUTION OF DIFFERENTIAL
NONLINEARITY (Minimum and Maximum)

14000
AVDD = 3 V
12000 REF = 5 V
TA = 25C
10000 15000 Devices
Frequency

8000

6000

4000

2000

0
±3.0 ±2.5 ±2.0 ±1.5 ±1.0 ±0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0
Integral Nonlinearity Min and Max (LSB) C039

Figure 44. TYPICAL DISTRIBUTION OF INTEGRAL

NONLINEARITY (Minimum and Maximum)

16 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

OVERVIEW

The ADS8885 is a high-speed, successive approximation register (SAR), analog-to-digital converter (ADC) from
a 16- and 18-bit product family. This compact device features high performance. Power consumption is
inherently low and scales linearly with sampling speed. The architecture is based on charge redistribution, which
inherently includes a sample-and-hold (S/H) function.
The ADS8885 supports a true-differential analog input across two pins (INP and INN). When a conversion is
initiated, the differential input on these pins is sampled on the internal capacitor array. While a conversion is in
progress, both the INP and INN inputs are disconnected from the internal circuit.
The ADS8885 uses an internal clock to perform conversions. The device reconnects the sampling capacitors to
the INP and INN pins after conversion and then enters an acquisition phase. During the acquisition phase, the
device is powered down and the conversion result can be read.
The device digital output is available in SPI-compatible format, which makes interfacing with microprocessors,
digital signal processors (DSPs), or field-programmable gate arrays (FPGAs) easy.

ANALOG INPUT
As shown in Figure 45, the device features a differential analog input. Both positive and negative inputs are
individually sampled on 55-pF sampling capacitors and the device converts for the voltage difference between
the two sampled values: VINP – VINN.
AVDD REF DVDD

REF

CONVST
AINP
Sample SCLK
and
SAR
ADC SPI
AINN Hold ADC DOUT

DIN
AGND REFM DGND
GND

GND

Figure 45. Detailed Block Diagram

Copyright © 2013, Texas Instruments Incorporated Submit Documentation Feedback 17

Product Folder Links: ADS8885
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

Most differential input SAR ADCs prohibit the input common-mode voltage, VCM (that is, the average voltage
between the inputs), at AINP or AINM from varying more than approximately 10% beyond the mid-scale input
value. As shown in Figure 46, the device has a unique common-mode voltage detection and rejection block that
does not have this restriction and thus allows VCM to be set to any value between 0 V and VREF without
degrading device performance.
REF

AINP
+ I
± N
T
Binary
E
2 Search
R
Algorithm
F
(SAR)
A
+ C
E
±
AINM
Common Mode Voltage
Detection and Rejection
Block

Figure 46. Conceptual Diagram: True Differential Input Structure

Table 4 shows the full-scale input range of the device as a function of input common-mode voltage. The device
offers a maximum dynamic range for VCM = VREF / 2. The differential input with wide common-mode range allows
connecting differential signals from sensors without any signal conditioning.

Table 4. Full-Scale Input Range

ABSOLUTE INPUT RANGE
VCM FULL SCALE INPUT RANGE (VFS)
VAINP VAINN
VCM < VREF / 2 0 to 2 × VCM 0 to 2 x VCM (–2 x VCM) to (2 x VCM)
VCM = VREF / 2 0 to VREF 0 to VREF (–VREF) to (VREF)
VCM > VREF / 2 (2 × VCM – VREF) to VREF (2 × VCM – VREF) to VREF (–2 × (VCM – VREF)) to (2 × (VCM – VREF))

Figure 47 shows an equivalent circuit of the input sampling stage. The sampling switch is represented by a 96-Ω
resistance in series with the ideal switch. Refer to the ADC Input Driver section for more details on the
recommended driving circuits.
96
Device in Hold Mode
AINP
4 pF 55 pF
REF

4 pF GND
55 pF
96
GND
AINN

Figure 47. Input Sampling Stage Equivalent Circuit

Figure 45 and Figure 47 illustrate electrostatic discharge (ESD) protection diodes to REF and GND from both
analog inputs. Make sure that these diodes do not turn on by keeping the analog inputs within the specified
range.

18 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

REFERENCE
The device operates with an external reference voltage and switches binary-weighted capacitors onto the
reference terminal (REF pin) during the conversion process. The switching frequency is proportional to the
internal conversion clock frequency but the dynamic charge requirements are a function of the absolute value of
the input voltage and reference voltage. This dynamic load must be supported by a reference driver circuit
without degrading the noise and linearity performance of the device. During the acquisition process, the device
automatically powers down and does not take any dynamic current from the external reference source. The basic
circuit diagram for such a reference driver circuit for precision ADCs is shown in Figure 48. Refer to the ADC
Reference Driver section for more details on the application circuits.

RREF_FLT
Voltage
Reference Buffer

RBUF_FLT
CREF_FLT
REF
CBUF_FLT
ADC

Figure 48. Reference Driver Schematic

CLOCK
The device uses an internal clock for conversion. Conversion duration may vary but is bounded by the minimum
and maximum value of tconv, as specified in the Timing Characteristics section. An external SCLK is only used for
a serial data read operation. Data are read after a conversion completes and when the device is in acquisition
phase for the next sample.

Copyright © 2013, Texas Instruments Incorporated Submit Documentation Feedback 19

Product Folder Links: ADS8885
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

ADC TRANSFER FUNCTION

The ADS8885 is a unipolar, differential input device. The device output is in twos compliment format.
Figure 49 shows ideal characteristics for the device. The full-scale range for the ADC input (AINP – AINN) is
equal to twice the reference input voltage to the ADC (2 × VREF). The LSB for the ADC is given by Equation 1.
1 LSB = [2 × (VREF / 218)] (1)

1FFFF
ADC Code (Hex)

00000
3FFFF

20001

20000 VIN
±VREF ±1 LSB 0 VREF
+ 1 LSB ± 1 LSB

Differential Analog Input

(AINP AINN)
Figure 49. Differential Transfer Characteristics

DIGITAL INTERFACE
The ADS8885 is a low pin-count device. However, the device offers six different options for interfacing with the
digital host.
These options can be broadly classified as being either CS mode (in either a 3- or 4-wire interface) or daisy-
chain mode. The device operates in CS mode if DIN is high at the CONVST rising edge. If DIN is low at the
CONVST rising edge, or if DIN and CONVST are connected together, the device operates in daisy-chain mode.
In both modes, the device can either operate with or without a busy indicator, where the busy indicator is a bit
preceding the output data bits that can be used to interrupt the digital host and trigger the data transfer.
The 3-wire interface in CS mode is useful for applications that need galvanic isolation on-board. The 4-wire
interface in CS mode allows the user to sample the analog input independent of the serial interface timing and,
therefore, allows easier control of an individual device while having multiple, similar devices on-board. The daisy-
chain mode is provided to hook multiple devices in a chain similar to a shift register and is useful in reducing
component count and the number of signal traces on the board.

CS Mode
CS mode is selected if DIN is high at the CONVST rising edge. There are four different interface options
available in this mode: 3-wire CS mode without a busy indicator, 3-wire CS mode with a busy indicator, 4-wire
CS mode without a busy indicator, and 4-wire CS mode with a busy indicator. The following sections discuss
these interface options in detail.
20 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

3-Wire CS Mode Without a Busy Indicator

This interface option is most useful when a single ADC is connected to an SPI-compatible digital host. In this
interface option, DIN can be connected to DVDD and CONVST functions as CS (as shown in Figure 50). As
shown in Figure 51, a CONVST rising edge forces DOUT to 3-state, samples the input signal, and causes the
device to enter a conversion phase. Conversion is done with the internal clock and continues regardless of the
state of CONVST. As a result, CONVST (functioning as CS) can be pulled low after the start of the conversion to
select other devices on the board. However, CONVST must return high before the minimum conversion time
(tconv-min) elapses and is held high until the maximum possible conversion time (tconv-max) elapses. A high level on
CONVST at the end of the conversion ensures the device does not generate a busy indicator.

DVDD CONVST CNV

DIN SCLK CLK

DOUT SDI

ADC
Digital Host
Figure 50. Connection Diagram: 3-Wire CS Mode Without a Busy Indicator (DIN = 1)

1/fsample
DIN = HIGH
CONVST = 1

CONVST

SCLK 1 2 3 16 17 18

DOUT D17 D16 D15 D2 D1 D0

tconv-max tACQ
tconv-min
ADC Acquiring
Converting
Conversion Result of Sample N Clocked-out
STATE Sample N while Acquiring Sample N+1
Sample N
End-of-Conversion

Figure 51. Interface Timing Diagram: 3-Wire CS Mode Without a Busy Indicator (DIN = 1)

When conversion is complete, the device enters an acquisition phase and powers down. CONVST (functioning
as CS) can be brought low after the maximum conversion time (tconv-max) elapses. On the CONVST falling edge,
DOUT comes out of 3-state and the device outputs the MSB of the data. The lower data bits are output on
subsequent SCLK falling edges. Data are valid on both SCLK edges. Data are valid on both edges of SCLK and
can be captured on either edge. However, a digital host capturing data on the SCLK falling edge can achieve a
faster reading rate (provided th_CK_DO is acceptable). DOUT goes to 3-state after the 18th SCLK falling edge or
when CONVST goes high, whichever occurs first.

Copyright © 2013, Texas Instruments Incorporated Submit Documentation Feedback 21

Product Folder Links: ADS8885
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

3-Wire CS Mode With a Busy Indicator

This interface option is most useful when a single ADC is connected to an SPI-compatible digital host and an
interrupt-driven data transfer is desired. In this interface option, DIN can be connected to DVDD and CONVST
functions as CS (as shown in Figure 52). The pull-up resistor on the DOUT pin ensures that the IRQ pin of the
digital host is held high when DOUT goes to 3-state. As shown in Figure 53, a CONVST rising edge forces
DOUT to 3-state, samples the input signal, and causes the device to enter a conversion phase. Conversion is
done with the internal clock and continues regardless of the state of CONVST. As a result, CONVST (functioning
as CS) can be pulled low after the start of the conversion to select other devices on the board. However,
CONVST must be pulled low before the minimum conversion time (tconv-min) elapses and must remain low until
the maximum possible conversion time (tconv-max) elapses. A low level on the CONVST input at the end of a
conversion ensures the device generates a busy indicator.

DVDD CONVST CNV

SCLK CLK
DIN DVDD

DOUT SDI

ADC IRQ

Digital Host
Figure 52. Connection Diagram: 3-Wire CS Mode With a Busy Indicator

1/fsample
DIN = DVDD

CONVST CONVST = 0

SCLK 1 2 3 17 18 19

DOUT SDO Pulled-up BUSY D17 D16 D2 D1 D0

tconv-max tACQ
tconv-min
ADC Acquiring Conversion Result of Sample N Clocked-out
Converting
STATE Sample N while Acquiring Sample N+1
Sample N
End-of-Conversion

Figure 53. Interface Timing Diagram: 3-Wire CS Mode With a Busy Indicator (DIN = 1)

When conversion is complete, the device enters an acquisition phase and powers down, DOUT comes out of 3-
state, and the device outputs a busy indicator bit (low level) on the DOUT pin. This configuration provides a high-
to-low transition on the IRQ pin of the digital host. The data bits are clocked out, MSB first, on the subsequent
SCLK falling edges. Data are valid on both SCLK edges. Data are valid on both edges of SCLK and can be
captured on either edge. However, a digital host capturing data on the SCLK falling edge can achieve a faster
reading rate (provided th_CK_DO is acceptable). DOUT goes to 3-state after the 19th SCLK falling edge or when
CONVST goes high, whichever occurs first.

22 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

4-Wire CS Mode Without a Busy Indicator

This interface option is useful when one or more ADCs are connected to an SPI-compatible digital host.
Figure 54 shows the connection diagram for single ADC, Figure 56 shows the connection diagram for two ADCs.

CS
CNV

DIN CONVST

DOUT SDI

SCLK

CLK

ADC
Digital Host
Figure 54. Connection Diagram: Single ADC with 4-Wire CS Mode Without a Busy Indicator

In this interface option, DIN is controlled by the digital host and functions as CS. As shown in Figure 55, with DIN
high, a CONVST rising edge selects CS mode, forces DOUT to 3-state, samples the input signal, and causes the
device to enter a conversion phase. In this interface option, CONVST must be held at a high level from the start
of the conversion until all data bits are read. Conversion is done with the internal clock and continues regardless
of the state of DIN. As a result, DIN (functioning as CS) can be pulled low to select other devices on the board.
However, DIN must be pulled high before the minimum conversion time (tconv-min) elapses and remains high until
the maximum possible conversion time (tconv-max) elapses. A high level on DIN at the end of the conversion
ensures the device does not generate a busy indicator.

1/fsample
tconv-max tACQ
tconv-min
CONVST
DIN = 1

DIN

SCLK 1 2 17 18

DOUT D17 D16 D1 D0
End-of-
Conversion
ADC Acquiring
Converting
Read Sample N
STATE Sample N
Sample N
Acquiring Sample N+1

Figure 55. Interface Timing Diagram: Single ADC with 4-Wire CS Mode Without a Busy Indicator

Copyright © 2013, Texas Instruments Incorporated Submit Documentation Feedback 23

Product Folder Links: ADS8885
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

When conversion is complete, the device enters acquisition phase and powers down. DIN (functioning as CS)
can be brought low after the maximum conversion time (tconv-max) elapses. On the DIN falling edge, DOUT comes
out of 3-state and the device outputs the MSB of the data. The lower data bits are output on subsequent SCLK
falling edges. Data are valid on both SCLK edges. Data are valid on both edges of SCLK and can be captured
on either edge. However, a digital host capturing data on the SCLK falling edge can achieve a faster reading rate
(provided th_CK_DO is acceptable). DOUT goes to 3-state after the 18th SCLK falling edge or when DIN goes high,
whichever occurs first.
As shown in Figure 56, multiple devices can be hooked together on the same data bus. In this case, as shown in
Figure 57, the DIN of the second device (functioning as CS for the second device) can go low after the first
device data are read and the DOUT of the first device is in 3-state.
Care must be taken so that CONVST and DIN are not both low together at any time during the cycle.

CS1
CS2
CNV

CONVST DIN CONVST DIN

DOUT DOUT SDI

SCLK SCLK

CLK

ADC #1 ADC #2
Digital Host
Figure 56. Connection Diagram: Two ADCs with 4-Wire CS Mode Without a Busy Indicator

1/fsample
tconv-max tACQ
tconv-min
CONVST
DIN = 1
DIN
(ADC 1) DIN = 1
DIN
(ADC 2)

SCLK 1 2 17 18 19 20 35 36

DOUT D17 D16 D1 D0 D17 D16 D1 D0
End-of-
Conversion
Read Sample N Read Sample N
ADC Acquiring
Converting ADC 1 ADC 2
STATE Sample N
Sample N
Acquiring Sample N+1

Figure 57. Interface Timing Diagram: Two ADCs with 4-Wire CS Mode Without a Busy Indicator

24 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

4-Wire CS Mode With a Busy Indicator

This interface option is most useful when a single ADC is connected to an SPI-compatible digital host and an
interrupt-driven data transfer is desired. In this interface option, the analog sample is least affected by clock jitter
because the CONVST signal (used to sample the input) is independent of the data read operation. In this
interface option, DIN is controlled by the digital host and functions as CS (as shown in Figure 58). The pull-up
resistor on the DOUT pin ensures that the IRQ pin of the digital host is held high when DOUT goes to 3-state. As
shown in Figure 59, when DIN is high, a CONVST rising edge selects CS mode, forces DOUT to 3-state,
samples the input signal, and causes the device to enter a conversion phase. In this interface option, CONVST
must be held high from the start of the conversion until all data bits are read. Conversion is done with the internal
clock and continues regardless of the state of DIN. As a result, DIN (acting as CS) can be pulled low to select
other devices on the board. However, DIN must be pulled low before the minimum conversion time (tconv-min)
elapses and remains low until the maximum possible conversion time (tconv-max) elapses. A low level on the DIN
input at the end of a conversion ensures the device generates a busy indicator.

DIN CONVST CNV

SCLK CLK
DVDD

DOUT SDI

ADC IRQ

Digital Host
Figure 58. Connection Diagram: 4-Wire CS Mode With a Busy Indicator

1/fsample
tconv-max tACQ
tconv-min
CONVST

DIN DIN =0

SCLK 1 2 3 17 18 19

DOUT SDO Pulled-up BUSY D17 D16 D2 D1 D0

ADC Acquiring
Converting
Conversion Result of Sample N Clocked-out
STATE Sample N while Acquiring Sample N+1
Sample N

Figure 59. Interface Timing Diagram: 4-Wire CS Mode With a Busy Indicator

Copyright © 2013, Texas Instruments Incorporated Submit Documentation Feedback 25

Product Folder Links: ADS8885
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

DAISY-CHAIN MODE
Daisy-chain mode is selected if DIN is low at the time of a CONVST rising edge or if DIN and CONVST are
connected together. Similar to CS mode, this mode features operation with or without a busy indicator. The
following sections discuss these interface modes in detail.

Daisy-Chain Mode Without a Busy Indicator

This interface option is most useful in applications where multiple ADC devices are used but the digital host has
limited interfacing capability. Figure 60 shows a connection diagram with N ADCs connected in the daisy-chain.
The CONVST pins of all ADCs in the chain are connected together and are controlled by a single pin of the
digital host. Similarly, the SCLK pins of all ADCs in the chain are connected together and are controlled by a
single pin of the digital host. The DIN pin for ADC 1 is connected to GND. The DOUT pin of ADC 1 is connected
to the DIN pin of ADC 2, and so on. The DOUT pin of the last ADC in the chain (ADC N) is connected to the SDI
pin of the digital host.

CNV

CONVST CONVST CONVST CONVST

DIN DOUT DIN DOUT } DIN DOUT DIN DOUT SDI

SCLK SCLK SCLK SCLK

CLK
ADC 1 ADC 2 } ADC N1 ADC N
Digital Host
Figure 60. Connection Diagram: Daisy-Chain Mode Without a Busy Indicator (DIN = 0)

As shown in Figure 61, the device DOUT pin is driven low when DIN and CONVST are low together. With DIN
low, a CONVST rising edge selects daisy-chain mode, samples the analog input, and causes the device to enter
a conversion phase. In this interface option, CONVST must remain high from the start of the conversion until all
data bits are read. When started, the conversion continues regardless of the state of SCLK, however SCLK must
be low at the CONVST rising edge so that the device does not generate a busy indicator at the end of the
conversion.
1/fsample
tconv-max tACQ
tconv-min
CONVST

SCLK 1 2 17 18 19 20 35 36

DIN 1 = LOW

DOUT 1 D17 D16 D1 D0
DIN 2

D17 D16 D1 D0 D17 D16 D1 D0
DOUT 2
End-of-
Conversion
Read Sample N Read Sample N
Acquiring
ADC Converting ADC 2 ADC 1
Sample N
STATE Sample N
Acquiring Sample N+1

Figure 61. Interface Timing Diagram: For Two devices in Daisy-Chain Mode Without a Busy Indicator

26 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

At the end of conversion, every ADC in the chain loads its own conversion result into the internal, 18-bit, shift
register and also outputs the MSB bit of this conversion result on its own DOUT pin. All ADCs enter an
acquisition phase and power-down. On every subsequent SCLK falling edge, the internal shift register of each
ADC latches the data available on its DIN pin and shifts out the next bit of data on its DOUT pin. Therefore, the
digital host receives the data of ADC N, followed by the data of ADC N–1, and so on (in MSB-first fashion). A
total of 18 x N SCLK falling edges are required to capture the outputs of all N devices in the chain. Data are valid
on both SCLK edges. Data are valid on both edges of SCLK and can be captured on either edge. However, a
digital host capturing data on the SCLK falling edge can achieve a faster reading rate (provided th_CK_DO is
acceptable).

Daisy-Chain Mode With a Busy Indicator

This interface option is most useful in applications where multiple ADC devices are used but the digital host has
limited interfacing capability and an interrupt-driven data transfer is desired. Figure 62 shows a connection
diagram with N ADCs connected in the daisy-chain. The CONVST pins of all ADCs in the chain are connected
together and are controlled by a single pin of the digital host. Similarly, the SCLK pins of all ADCs in the chain
are connected together and are controlled by a single pin of the digital host. The DIN pin for ADC 1 is connected
to its CONVST. The DOUT pin of ADC 1 is connected to the DIN pin of ADC 2, and so on. The DOUT pin of the
last ADC in the chain (ADC N) is connected to the SDI and IRQ pins of the digital host.

CNV

CONVST CONVST CONVST CONVST IRQ

DIN DOUT DIN DOUT } DIN DOUT DIN DOUT SDI

SCLK SCLK SCLK SCLK

CLK
ADC 1 ADC 2 } ADC N1 ADC N
Digital Host

Figure 62. Connection Diagram: Daisy-Chain Mode With a Busy Indicator (DIN = 0)

Copyright © 2013, Texas Instruments Incorporated Submit Documentation Feedback 27

Product Folder Links: ADS8885
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

As shown in Figure 63, the device DOUT pin is driven low when DIN and CONVST are low together. A CONVST
rising edge selects daisy-chain mode, samples the analog input, and causes the device to enter a conversion
phase. In this interface option, CONVST must remain high from the start of the conversion until all data bits are
read. When started, the conversion continues regardless of the state of SCLK, however SCLK must be high at
the CONVST rising edge so that the device generates a busy indicator at the end of the conversion.
1/fsample
tconv-max tACQ
tconv-min
CONVST

SCLK th-DI-CNV 1 2 18 19 20 21 36 37

DIN 1 =
CONVST

DOUT 1 BUSY D17 D1 D0
DIN 2

BUSY D17 D1 D0 D17 D16 D1 D0
DOUT 2
End-of-
Conversion
Read Sample N Read Sample N
Acquiring
ADC Converting ADC 2 ADC 1
Sample N
STATE Sample N
Acquiring Sample N+1

Figure 63. Interface Timing Diagram: For Two Devices in Daisy-Chain Mode With a Busy Indicator

At the end of conversion, every ADC in the chain loads its own conversion result into the internal, 18-bit, shift
register and also forces its DOUT pin high, thereby providing a low-to-high transition on the IRQ pin of the digital
host. All ADCs enter an acquisition phase and power-down. On every subsequent SCLK falling edge, the internal
shift register of each ADC latches the data available on its DIN pin and shifts out the next bit of data on its DOUT
pin. Therefore, the digital host receives the interrupt signal followed by the data of ADC N followed by the data of
ADC N–1, and so on (in MSB-first fashion). A total of (18 x N) + 1 SCLK falling edges are required to capture the
outputs of all N devices in the chain. Data are valid on both edges of SCLK and can be captured on either edge.
However, a digital host capturing data on the SCLK falling edge can achieve a faster reading rate (provided
th_CK_DO is acceptable). Note that the busy indicator bits of ADC 1 to ADC N–1 do not propagate to the next
device in the chain.

POWER SUPPLY
The device has two separate power supplies: AVDD and DVDD. The internal circuits of the device operate on
AVDD; DVDD is used for the digital interface. AVDD and DVDD can be independently set to any value within the
permissible range.
Decouple the AVDD and DVDD pins with GND, using individual 1-µF decoupling capacitors placed in close
proximity to the pin, as shown in Figure 64.

Digital
Supply
Analog REF DVDD
Supply
AVDD DIN 1 µF

1 µF AINP SCLK

AINN DOUT

GND CONVST

Figure 64. Supply Decoupling

28 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

POWER SAVING
The device has an auto power-down feature that powers down the internal circuitry at the end of every
conversion. Referring to Figure 65, the input signal is acquired on the sampling capacitors when the device is in
a power-down state (tacq); at the same time, the result for the previous conversion is available for reading. The
device powers up on the start of the next conversion. During conversion phase (tconv), the device also consumes
current from the reference source (connected to pin REF).

tTHROUGHPUT 2 * tTHROUGHPUT

Device Phase
tCONV tACQ tCONV tACQ

~50000X ~50000X

IAVDD

~1200X ~1200X

IREF

~2X
IAVG(AVDD+REF)

Figure 65. Power Scaling with Throughput

The conversion time, tconv, is independent of the SCLK frequency. When operating the device at speeds lower
than the maximum rated throughput, the conversion time, tconv, does not change; the device spends more time in
power-down state. Therefore, as shown in Figure 66, the device power consumption from the AVDD supply and
the external reference source is directly proportional to the speed of operation. Extremely low AVDD power-down
current (50 nA, typical) and extremely low external reference leakage current (250 nA, typical), make this device
ideal for very low throughput applications (such as pulsed measurements).
1
Analog Supply Current (mA)

0.8

0.6

0.4

0.2

0
40 100 160 220 280 340 400
Throughput (kSPS) C03

Figure 66. Power Scaling with Throughput

Copyright © 2013, Texas Instruments Incorporated Submit Documentation Feedback 29

Product Folder Links: ADS8885
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

APPLICATION INFORMATION

The two primary circuits required to maximize the performance of a high-precision, successive approximation
register (SAR), analog-to-digital converter (ADC) are the input driver and the reference driver circuits. This
section details some general principles for designing these circuits, followed by some application circuits
designed using the ADS8885.

ADC REFERENCE DRIVER

The external reference source to the ADS8885 must provide low-drift and very accurate voltage for the ADC
reference input and support the dynamic charge requirements without affecting the noise and linearity
performance of the device. The output broadband noise of most references can be in the order of a few 100
μVRMS. Therefore, to prevent any degradation in the noise performance of the ADC, the output of the voltage
reference must be appropriately filtered by using a low-pass filter with a cutoff frequency of a few hundred Hertz.
After band-limiting the noise of the reference circuit, the next important step is to design a reference buffer that
can drive the dynamic load posed by the reference input of the ADC. The reference buffer must regulate the
voltage at the reference pin such that the value of VREF stays within the 1-LSB error at the start of each
conversion. This condition necessitates the use of a large capacitor, CBUF_FLT (refer to Figure 48) for regulating
the voltage at the reference input of the ADC. The amplifier selected to drive the reference pin should have an
extremely low offset and temperature drift with a low output impedance to drive the capacitor at the ADC
reference pin without any stability issues.

Reference Driver Circuit for VREF = 4.5 V

The application circuit in Figure 67 shows the schematic of a complete reference driver circuit that generates a
voltage of 4.5 V dc using a single 5-V supply. This circuit is suitable to drive the reference of the ADS8885 at
higher sampling rates up to 400 kSPS. The 4.5-V reference voltage in this design is generated by the high-
precision, low-noise REF5045 circuit. The output broadband noise of the reference is heavily filtered by a low-
pass filter with a 3-dB cutoff frequency of 160 Hz.
20 k

1 µF

-
- 1 k AVDD
AVDD +
REF5045 1 k +
THS4281
+ 0.2
Vin Vout + OPA333 1 µF
AVDD REF AVDD
Temp 1 µF AVDD V
AINP CONVST
10 µF +
Gnd Trim ADS8885
AINM
GND
1 µF

Figure 67. Schematic of Reference Driver Circuit with VREF = 4.5 V

The reference buffer is designed with the THS4281 and OPA333 in a composite architecture to achieve superior
dc and ac performance at a reduced power consumption, compared to using a single high-performance amplifier.
The THS4281 is a high-bandwidth amplifier with a very low output impedance of 1 Ω at a frequency of 1 MHz.
The low output impedance makes the THS4281 a good choice for driving a high capacitive load to regulate the
voltage at the reference input of the ADC. The high offset and drift specifications of the THS4281 are corrected
by using a dc-correcting amplifier (OPA333) inside the feedback loop. The composite scheme inherits the
extremely low offset and temperature drift specifications of the OPA333.

For step-by-step design procedure, circuit schematics, bill of materials, PCB files, simulation results, and test
results, using a similar device, refer to 18-Bit Data Acquisition (DAQ) Block Optimized for 1-μs Full-Scale Step
Response (SLAU512).

30 Submit Documentation Feedback Copyright © 2013, Texas Instruments Incorporated

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

Reference Driver Circuit for VREF = 2.5 V in Ultralow Power, Lower Throughput Applications
The application circuit in Figure 68 shows the schematic of a complete reference driver circuit that generates a
voltage of 2.5 V dc using a single 3.3-V supply. This ultralow power reference block is suitable to drive the
ADS8885 for power-sensitive applications at a relatively lower throughput. This design uses the high-precision
REF3325 circuit that provides an accurate 2.5-V reference voltage at an extremely low quiescent current of 5 µA.
The output broadband noise of the reference is heavily filtered by a low-pass filter with a 3-dB cutoff frequency of
16 Hz.
1 k

1 µF

AVDD
- 4.7
REF3325
10 k
IN OUT + +
OPA333 REF AVDD
AVDD GND AINP
V+ CONVST
22 µF
1 µF ADS8885
AVDD
AINM
GND

Figure 68. Schematic of Reference Driver Circuit with VREF = 2.5 V DC

The reference buffer is designed using the low-power OPA333 that can operate from a 3.3-V supply at an
extremely low quiescent current of 28 µA. The wideband noise contribution from the amplifier is limited by a low-
pass filter of a cutoff frequency equal to 1.5 kHz, formed by a 4.7-Ω resistor in combination with a 22-µF
capacitor. The 4.7-Ω series resistor creates an additional drop in the reference voltage, which is corrected by a
dual-feedback configuration.

For step-by-step design procedure, circuit schematics, bill of materials, PCB files, simulation results, and test
results, using a similar device, refer to 18-Bit, 10kSPS Data Acquisition (DAQ) Block Optimized for Ultra Low
Power < 1mW (SLAU514).

Product Folder Links: ADS8885
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

ADC INPUT DRIVER

The input driver circuit for a high-precision ADC mainly consists of two parts: a driving amplifier and a fly-wheel
RC filter. The amplifier is used for signal conditioning of the input voltage and its low output impedance provides
a buffer between the signal source and the switched capacitor inputs of the ADC. The RC filter helps attenuate
the sampling charge injection from the switched-capacitor input stage of the ADC and functions as an antialiasing
filter to band-limit the wideband noise contributed by the front-end circuit. Careful design of the front-end circuit is
critical to meet the linearity and noise performance of a high-precision, 18-bit ADC such as the ADS8885.

Input Amplifier Selection

Selection criteria for the input amplifiers is highly dependent on the input signal type as well as the performance
goals of the data acquisition system. Some key amplifier specifications to consider while selecting an appropriate
amplifier to drive the inputs of the ADC are:
• Small-signal bandwidth. Select the small-signal bandwidth of the input amplifiers to be as high as possible
after meeting the power budget of the system. Higher bandwidth reduces the closed-loop output impedance
of the amplifier, thus allowing the amplifier to more easily drive the low cutoff frequency RC filter (refer to the
Antialiasing Filter section) at the inputs of the ADC. Higher bandwidth also minimizes the harmonic distortion
at higher input frequencies. In order to maintain the overall stability of the input driver circuit, the amplifier
bandwidth should be selected as described in Equation 2:
§ 1 ·
Unity Gain Bandwidth t 4 u ¨¨ ¸¸
© 2S u RFLT u CFLT ¹ (2)
• Noise. Noise contribution of the front-end amplifiers should be as low as possible to prevent any degradation
in SNR performance of the system. As a rule of thumb, to ensure that the noise performance of the data
acquisition system is not limited by the front-end circuit, the total noise contribution from the front-end circuit
should be kept below 20% of the input-referred noise of the ADC. Noise from the input driver circuit is band-
limited by designing a low cutoff frequency RC filter, as explained in Equation 3.
§ SNRdB ·
2
§ V 1 _ AM P_ PP · ¨ ¸
¨ ¸ S 1 VREF
NG u 2 u ¨ f ¸ en2 _ RM S u u f3dB d u u 10 © 20 ¹
¨ 6 . 6 ¸ 2 5 2
© ¹
where:
• V1 / f_AMP_PP is the peak-to-peak flicker noise in µVRMS,
• en_RMS is the amplifier broadband noise density in nV/√Hz,
• f–3dB is the 3-dB bandwidth of the RC filter, and
• NG is the noise gain of the front-end circuit, which is equal to '1' in a buffer configuration. (3)
• Distortion. Both the ADC and the input driver introduce nonlinearity in a data acquisition block. As a rule of
thumb, to ensure that the distortion performance of the data acquisition system is not limited by the front-end
circuit, the distortion of the input driver should be at least 10 dB lower than the distortion of the ADC, as
shown in Equation 4.
THD AMP d THD ADC 10 dB (4)
• Settling Time. For dc signals with fast transients that are common in a multiplexed application, the input signal
must settle within an 18-bit accuracy at the device inputs during the acquisition time window. This condition is
critical to maintain the overall linearity performance of the ADC. Typically, the amplifier data sheets specify
the output settling performance only up to 0.1% to 0.001%, which may not be sufficient for the desired 18-bit
accuracy. Therefore, the settling behavior of the input driver should always be verified by TINA™-SPICE
simulations before selecting the amplifier.

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

Antialiasing Filter
Converting analog-to-digital signals requires sampling an input signal at a constant rate. Any higher frequency
content in the input signal beyond half the sampling frequency is digitized and folded back into the low-frequency
spectrum. This process is called aliasing. Therefore, an analog, antialiasing filter must be used to remove the
harmonic content from the input signal before being sampled by the ADC. An antialiasing filter is designed as a
low-pass, RC filter, for which the 3-dB bandwidth is optimized based on specific application requirements. For dc
signals with fast transients (including multiplexed input signals), a high-bandwidth filter is designed to allow
accurately settling the signal at the inputs of the ADC during the small acquisition time window. For ac signals,
the filter bandwidth should be kept low to band-limit the noise fed into the input of the ADC, thereby increasing
the signal-to-noise ratio (SNR) of the system.
Besides filtering the noise from the front-end drive circuitry, the RC filter also helps attenuate the sampling
charge injection from the switched-capacitor input stage of the ADC. A differential capacitor, CFLT, is connected
across the inputs of the ADC (as shown in Figure 69). This capacitor helps reduce the sampling charge injection
and provides a charge bucket to quickly charge the internal sample-and-hold capacitors during the acquisition
process. As a rule of thumb, the value of this capacitor should be at least 10 times the specified value of the
ADC sampling capacitance. For the ADS8885, the input sampling capacitance is equal to 59 pF, thus the value
of CFLT should be greater than 590 pF. The capacitor should be a COG- or NPO-type because these capacitor
types have a high-Q, low-temperature coefficient, and stable electrical characteristics under varying voltages,
frequency, and time.
RFLT 22

1 V
AINP
f 3 dB +
2S u R FLT R FLT u C FLT CFLT 590 pF ADS8885
AINM
GND

RFLT 22

Figure 69. Antialiasing Filter

Note that driving capacitive loads can degrade the phase margin of the input amplifiers, thus making the amplifier
marginally unstable. To avoid amplifier stability issues, series isolation resistors (RFLT) are used at the output of
the amplifiers. A higher value of RFLT is helpful from the amplifier stability perspective, but adds distortion as a
result of interactions with the nonlinear input impedance of the ADC. Distortion increases with source impedance,
input signal frequency, and input signal amplitude. Therefore, the selection of RFLT requires balancing the stability
and distortion of the design. For the ADS8885, TI recommends limiting the value of RFLT to a maximum of 22 Ω
in order to avoid any significant degradation in linearity performance. The tolerance of the selected resistors can
be chosen as 1% because the use of a differential capacitor at the input balances the effects resulting from any
resistor mismatch.
The input amplifier bandwidth should be much higher than the cutoff frequency of the antialiasing filter. TI
strongly recommends performing a SPICE simulation to confirm that the amplifier has more than 40° phase
margin with the selected filter. Simulation is critical because even with high-bandwidth amplifiers, some amplifiers
might require more bandwidth than others to drive similar filters. If an amplifier has less than a 40° phase margin
with 22-Ω resistors, using a different amplifier with higher bandwidth or reducing the filter cutoff frequency with a
larger differential capacitor is advisable.

Product Folder Links: ADS8885
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

APPLICATION CIRCUIT EXAMPLES

This section describes some common application circuits using the ADS8885. These data acquisition (DAQ)
blocks are optimized for specific input types and performance requirements of the system. For simplicity, power-
supply decoupling capacitors are not shown in these circuit diagrams; refer to the Power Supply section for
suggested guidelines.

DAQ Circuit for a 2.5-µs, Full-Scale Step Response

The application circuit shown in Figure 70 is optimized for using the ADS8885 at the maximum-specified
throughput of 400 kSPS for a full-scale step input voltage. Such step input signals are common in multiplexed
applications when switching between different channels. In a worst-case scenario, one channel is at the negative
full-scale (NFS) and the other channel is at the positive full-scale (PFS) voltage, in which case the step size is
the full-scale range (FSR) of the ADC when the MUX channel is switched.
In such applications, the primary design requirement is to ensure that the full-scale step input signal settles to 18-
bit accuracy at the ADC inputs. This condition is critical to achieve the excellent linearity specifications of the
ADC. Therefore, the bandwidth of the antialiasing RC filter should be large enough to allow optimal settling of the
input signal during the ADC acquisition time. The filter capacitor helps reduce the sampling charge injection at
the ADC inputs, but degrades the phase margin of the driving amplifier, thereby leading to stability issues.
Amplifier stability is maintained by the series isolation resistor. Therefore, the component values of the
antialiasing filter should be carefully selected to meet the settling requirements of the system as well as to
maintain the stability of the input driving amplifiers.
For the input driving amplifiers, key specifications include rail-to-rail input and output swing, high bandwidth, high
slew rate, and fast settling time. The OPA350 CMOS amplifier meets all these specification requirements for this
circuit with a single-supply and low quiescent current.

20 k REFERENCE DRIVE CIRCUIT

1 µF

-
THS4281 1 k -
+ AVDD
+ OPA333 1 k REF5045
0.2 +
1 µF + Vout Vin
AVDD
AVDD 1 µF Temp
10 µF
Trim Gnd

1 µF

AVDD

+ AVDD
+
+

VIN+ OPA350
10
-
REF AVDD
VCM V
AINP CONVST
+
1 nF ADS8885
AINM
GND CONVST
VIN-
- 10
+

OPA350
+
+
18-Bit 400-kSPS
INPUT DRIVER SAR ADC
AVDD

Figure 70. DAQ Circuit for 2.5-µs, Full-Scale Step Response

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

Low-Power DAQ Circuit for Excellent Dynamic Performance at 400 kSPS

The application circuit shown in Figure 71 is optimized for using the ADS8885 at the maximum specified
throughput of 400 kSPS for a full-scale sinusoidal signal of 10-kHz frequency. This circuit achieves excellent
dynamic performance for the lowest power consumption. The differential ac input signal is processed through
low-noise and low-power amplifiers configured as unity-gain buffers and a low-pass, RC filter before being fed
into the ADC.
In such applications, the input driver must be low in power and noise as well as able to support rail-to-rail input
and output swing with a single supply. A high amplifier bandwidth is also preferred to help attenuate high-
frequency distortion. However, oftentimes bandwidth and noise are traded off with the power consumption of the
amplifier. This circuit uses the OPA320 as the front-end driving amplifier because this device has a relatively low
noise density of 7 nV/√Hz for a maximum-specified quiescent current of 1.45 mA per channel.
The noise contribution from the front-end amplifier is band-limited by the 3-dB bandwidth of the RC filter, which is
designed to be 165 kHz in this application. Again, the component values of the antialiasing filter are carefully
selected to maintain the stability of the input driving amplifiers.

20 k REFERENCE DRIVE CIRCUIT

1 µF

-
THS4281 1 k -
+ AVDD
+ OPA333
1 k REF5045
0.2 +
1 µF + Vout Vin
AVDD
AVDD 1 µF Temp
10 µF
Trim Gnd

1 µF

AVDD

+ AVDD
+
+

VIN+ OPA320
22
-
REF AVDD
VCM V
AINP CONVST
+
22 nF ADS8885
AINM
GND CONVST
VIN-
- 22
+

OPA320
+
+
18-Bit 400-kSPS
INPUT DRIVER SAR ADC
AVDD

Figure 71. DAQ Circuit for Lowest Power and Excellent Dynamic Performance at 400 kSPS

For step-by-step design procedure, circuit schematics, bill of materials, PCB files, simulation results, and test
results, using a similar device, refer to 18-Bit, 1-MSPS Data Acquisition (DAQ) Block Optimized for Lowest
Power (SLAU513).

Product Folder Links: ADS8885
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

DAQ Circuit for Lowest Distortion and Noise Performance at 400 kSPS
This section describes two application circuits (Figure 72 and Figure 73) that are optimized for using the
ADS8885 with lowest distortion and noise performance at a throughput of 400 kSPS. In both applications, the
input signal is processed through a high-bandwidth, low-distortion, fully-differential amplifier (FDA) designed in an
inverting gain configuration and a low-pass RC filter before being fed into the ADC.
As a rule of thumb, the distortion from the input driver should be at least 10 dB less than the ADC distortion. The
distortion resulting from variation in the common-mode signal is eliminated by using the FDA in an inverting gain
configuration that establishes a fixed common-mode level for the circuit. This configuration also eliminates the
requirement of a rail-to-rail swing at the amplifier input. Therefore, these circuits use the low-power THS4521 as
an input driver, which provides exceptional ac performance because of its extremely low-distortion and high-
bandwidth specifications.
In addition, the components of the antialiasing filter are such that the noise from the front-end circuit is kept low
without adding distortion to the input signal.

Differential Input Configuration

The circuit in Figure 72 shows a fully-differential DAQ block optimized for low distortion and noise using the
THS4521 and ADS8885. This front-end circuit configuration requires a differential signal at the input of the FDA
and provides a differential output to drive the ADC inputs. The common-mode voltage of the input signal provided
to the ADC is set by the VOCM pin of the THS4521 (not shown in Figure 72). To use the complete dynamic range
of the ADC, VOCM can be set to VREF / 2 by using a simple resistive divider. However, note that the ADS8885
allows the common-mode input voltage (VCM) to be set to any value in the range of 0 V to VREF.

20 k REFERENCE DRIVE CIRCUIT

1 µF

-
THS4281 1 k -
+ AVDD
+ OPA333
1 k REF5045
0.2 +
1 µF + Vout Vin
AVDD
AVDD Temp
10 µF 1 µF
Trim Gnd

1 µF

1 K 1 K
AVDD
AVDD
VIN+

+ 10 REF AVDD
VCM + - V
AINP CONVST

THS4521 +
10 nF ADS8885
- + AINM
GND CONVST
10
VIN-
+

1 K 1 K
18-Bit 400-kSPS
INPUT DRIVER SAR ADC

Figure 72. Differential Input DAQ Circuit for Lowest Distortion and Noise at 400 kSPS

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

Single-Ended to Differential Configuration

The circuit in Figure 73 shows a single-ended to differential DAQ block optimized for low distortion and noise
using the THS4521 and the ADS8885. This front-end circuit configuration requires a single-ended ac signal at
the input of the FDA and provides a fully-differential output to drive the ADC inputs. The common-mode voltage
of the input signal provided to the ADC is set by the VOCM pin of the THS4521 (not shown in Figure 73). To use
the complete dynamic range of the ADC, VOCM can be set to VREF / 2 by using a simple resistive divider.
However, note that the ADS8885 allows the common-mode input voltage (VCM) to be set to any value in the
range of 0 V to VREF.

20 k REFERENCE DRIVE CIRCUIT

1 µF

-
THS4281 1 k -
+ AVDD
+ OPA333
1 k REF5045
0.2 +
1 µF + Vout Vin
AVDD
AVDD 1 µF Temp
10 µF
Trim Gnd

1 µF

1 K 1 K
AVDD
AVDD
VIN+

+ 10 REF AVDD
+ - V
AINP CONVST

THS4521 +
10 nF ADS8885
- + AINM
GND CONVST
10

1 K 1 K
18-Bit 400-kSPS
INPUT DRIVER SAR ADC

Figure 73. Single-Ended to Differential DAQ Circuit for Lowest Distortion and Noise at 400 kSPS

Product Folder Links: ADS8885
ADS8885

SBAS568A – MAY 2013 – REVISED DECEMBER 2013 www.ti.com

Ultralow-Power DAQ Circuit at 10 kSPS

The data acquisition circuit shown in Figure 74 is optimized for using the ADS8885 at a reduced throughput of 10
kSPS with ultralow-power consumption (< 1 mW) targeted at portable and battery-powered applications.
In order to save power, this circuit is operated on a single 3.3-V supply. The circuit uses extremely low-power,
dual amplifiers (such as the OPA2333) with a maximum quiescent current of 28 µA per channel to drive the ADC
inputs. The input amplifiers are configured in a modified unity-gain buffer configuration. The filter capacitor at the
ADC inputs attenuates the sampling charge-injection noise from the ADC but effects the stability of the input
amplifiers by degrading the phase margin. This attenuation requires a series isolation resistor to maintain
amplifier stability. The value of the series resistor is directly proportional to the open-loop output impedance of
the driving amplifier to maintain stability, which is high (in the order of kΩ) in the case of low-power amplifiers
such as the OPA333. Therefore, a high value of 1 kΩ is selected for the series resistor at the ADC inputs.
However, this series resistor creates an additional voltage drop in the signal path, thereby leading to linearity and
distortion issues. The dual-feedback configuration used in Figure 74 corrects for this additional voltage drop and
maintains system performance at ultralow-power consumption.
1 k
REFERENCE DRIVE CIRCUIT
1 µF

- 4.7
REF3325 OPA333
10 k
IN OUT + +
AVDD GND
22 µF
1 µF
AVDD

10 k
AVDD

10 nF

REF AVDD
AINP CONVST

ADS8885
AINM
- 1 k GND CONVST
OPA333
+

VIN+ + +

VCM
AVDD
4.7 nF

VIN-
+ + 1 k
+

OPA333
ADS8885 running at 10 kSPS
-

10 nF

10 k
INPUT DRIVER

Figure 74. Ultralow-Power DAQ Circuit at 10 kSPS

Product Folder Links: ADS8885

ADS8885

www.ti.com SBAS568A – MAY 2013 – REVISED DECEMBER 2013

REVISION HISTORY
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.

Changes from Original (May 2013) to Revision A Page

• Changed Wide Common-Mode Voltage Range Features bullet .......................................................................................... 1

• Changed sub-bullets of AC and DC Performance Features bullet ....................................................................................... 1
• Changed Full-Scale Step Settling Features bullet ................................................................................................................ 1
• Deleted last two Applications bullets .................................................................................................................................... 1
• Changed Description section ................................................................................................................................................ 1
• Changed front page graphic ................................................................................................................................................. 1
• Added Family Information, Absolute Maximum Ratings, and Thermal Information tables ................................................... 2
• Added Electrical Characteristics table .................................................................................................................................. 3
• Added Timing Characteristics section .................................................................................................................................. 5
• Added Pin Configurations section ......................................................................................................................................... 9
• Added Typical Characteristics section ................................................................................................................................ 10
• Added Overview section ..................................................................................................................................................... 17
• Added Application Information section ............................................................................................................................... 30

Product Folder Links: ADS8885
PACKAGE OPTION ADDENDUM

www.ti.com 10-Dec-2020

PACKAGING INFORMATION

Orderable Device Status Package Type Package Pins Package Eco Plan Lead finish/ MSL Peak Temp Op Temp (°C) Device Marking Samples
(1) Drawing Qty (2) Ball material (3) (4/5)
(6)

ADS8885IDGS ACTIVE VSSOP DGS 10 80 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 85 8885

ADS8885IDGSR ACTIVE VSSOP DGS 10 2500 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 85 8885

ADS8885IDRCR ACTIVE VSON DRC 10 3000 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 85 8885

ADS8885IDRCT ACTIVE VSON DRC 10 250 RoHS & Green NIPDAU Level-2-260C-1 YEAR -40 to 85 8885

(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.

(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based
flame retardants must also meet the <=1000ppm threshold requirement.

(3)
MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.

(4)
There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.

(5)
Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.

(6)
Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two
lines if the finish value exceeds the maximum column width.

Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and

Addendum-Page 1
PACKAGE OPTION ADDENDUM

www.ti.com 10-Dec-2020

continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.

In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.

Addendum-Page 2
PACKAGE MATERIALS INFORMATION

www.ti.com 5-Jan-2022

TAPE AND REEL INFORMATION

*All dimensions are nominal

Device Package Package Pins SPQ Reel Reel A0 B0 K0 P1 W Pin1
Type Drawing Diameter Width (mm) (mm) (mm) (mm) (mm) Quadrant
(mm) W1 (mm)
ADS8885IDGSR VSSOP DGS 10 2500 330.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1
ADS8885IDRCR VSON DRC 10 3000 330.0 12.4 3.3 3.3 1.1 8.0 12.0 Q2
ADS8885IDRCT VSON DRC 10 250 180.0 12.4 3.3 3.3 1.1 8.0 12.0 Q2

Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION

www.ti.com 5-Jan-2022

*All dimensions are nominal

Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)
ADS8885IDGSR VSSOP DGS 10 2500 367.0 367.0 35.0
ADS8885IDRCR VSON DRC 10 3000 367.0 367.0 35.0
ADS8885IDRCT VSON DRC 10 250 210.0 185.0 35.0

Pack Materials-Page 2
PACKAGE MATERIALS INFORMATION

www.ti.com 5-Jan-2022

TUBE

*All dimensions are nominal

Device Package Name Package Type Pins SPQ L (mm) W (mm) T (µm) B (mm)
ADS8885IDGS DGS VSSOP 10 80 330.2 6.6 3005 1.88

Pack Materials-Page 3
PACKAGE OUTLINE
DGS0010A SCALE 3.200
VSSOP - 1.1 mm max height
SMALL OUTLINE PACKAGE

C
5.05
TYP SEATING PLANE
4.75

A PIN 1 ID 0.1 C
AREA

8X 0.5
10
1

3.1
2.9 2X
NOTE 3 2

5
6
0.27
10X
0.17
3.1 0.1 C A B 1.1 MAX
B
2.9
NOTE 4

0.23
TYP
SEE DETAIL A 0.13

0.25
GAGE PLANE

0.7 0.15
0 -8 0.05
0.4

DETAIL A
TYPICAL

4221984/A 05/2015

NOTES:

1. All linear dimensions are in millimeters. Any dimensions in parenthesis are for reference only. Dimensioning and tolerancing
per ASME Y14.5M.
2. This drawing is subject to change without notice.
3. This dimension does not include mold flash, protrusions, or gate burrs. Mold flash, protrusions, or gate burrs shall not
exceed 0.15 mm per side.
4. This dimension does not include interlead flash. Interlead flash shall not exceed 0.25 mm per side.
5. Reference JEDEC registration MO-187, variation BA.

www.ti.com
EXAMPLE BOARD LAYOUT
DGS0010A VSSOP - 1.1 mm max height
SMALL OUTLINE PACKAGE

10X (1.45)
10X (0.3) SYMM (R0.05)
1 TYP
10

SYMM

8X (0.5) 5 6

(4.4)

LAND PATTERN EXAMPLE

SCALE:10X

SOLDER MASK METAL UNDER SOLDER MASK

METAL OPENING
OPENING SOLDER MASK

0.05 MAX 0.05 MIN

ALL AROUND ALL AROUND

NON SOLDER MASK SOLDER MASK

DEFINED DEFINED

SOLDER MASK DETAILS

NOT TO SCALE

4221984/A 05/2015
NOTES: (continued)

6. Publication IPC-7351 may have alternate designs.

7. Solder mask tolerances between and around signal pads can vary based on board fabrication site.

www.ti.com
EXAMPLE STENCIL DESIGN
DGS0010A VSSOP - 1.1 mm max height
SMALL OUTLINE PACKAGE

10X (1.45)
SYMM (R0.05) TYP
10X (0.3)
1
10

SYMM
8X (0.5)

5 6

(4.4)

SOLDER PASTE EXAMPLE

BASED ON 0.125 mm THICK STENCIL
SCALE:10X

4221984/A 05/2015
NOTES: (continued)

8. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate
design recommendations.
9. Board assembly site may have different recommendations for stencil design.

www.ti.com
GENERIC PACKAGE VIEW
DRC 10 VSON - 1 mm max height
3 x 3, 0.5 mm pitch PLASTIC SMALL OUTLINE - NO LEAD

This image is a representation of the package family, actual package may vary.
Refer to the product data sheet for package details.

4226193/A

www.ti.com
PACKAGE OUTLINE
DRC0010D SCALE 3.800
VSON - 1 mm max height
PLASTIC SMALL OUTLINE - NO LEAD

3.1
B A
2.9

3.1
PIN 1 INDEX AREA
2.9

1 MAX C

SEATING PLANE

0.08 C

1.05 0.1 (0.2) TYP

EXPOSED 0.05
4X (0.23) 0.00
THERMAL PAD

5
6

2X
11
2 2.55 0.1

10
1
8X 0.5
0.30
10X
0.18
PIN 1 ID 0.5
10X 0.1 C A B
(OPTIONAL) 0.3
0.05 C

4218880/A 10/2020

NOTES:

www.ti.com
EXAMPLE BOARD LAYOUT
DRC0010D VSON - 1 mm max height
PLASTIC SMALL OUTLINE - NO LEAD

(1.05)
10X (0.6)

10
1

10X (0.24)
(1.025)

SYMM 11
(2.55)
8X (0.5)

(R0.05) TYP
5 6

( 0.2) VIA SYMM

TYP
(2.8)

LAND PATTERN EXAMPLE

SCALE:20X

0.07 MAX 0.07 MIN

ALL AROUND ALL AROUND

SOLDER MASK METAL METAL UNDER SOLDER MASK

OPENING SOLDER MASK OPENING
NON SOLDER MASK
DEFINED SOLDER MASK
(PREFERRED) DEFINED

SOLDER MASK DETAILS

4218880/A 10/2020

NOTES: (continued)

4. This package is designed to be soldered to a thermal pad on the board. For more information, see Texas Instruments literature
number SLUA271 (www.ti.com/lit/slua271).
5. Vias are optional depending on application, refer to device data sheet. If some or all are implemented, recommended via locations are shown.

www.ti.com
EXAMPLE STENCIL DESIGN
DRC0010D VSON - 1 mm max height
PLASTIC SMALL OUTLINE - NO LEAD

SYMM METAL
10X (0.6) TYP

1 10

10X (0.24)
(0.665)
11 SYMM

8X (0.5)

2X (1.13)
(R0.05) TYP
5 6

2X(0.99)

(2.8)

SOLDER PASTE EXAMPLE

BASED ON 0.125 mm THICK STENCIL

EXPOSED PAD 11:

84% PRINTED SOLDER COVERAGE BY AREA UNDER PACKAGE
SCALE:20X

4218880/A 10/2020
NOTES: (continued)

6. Laser cutting apertures with trapezoidal walls and rounded corners may offer better paste release. IPC-7525 may have alternate
design recommendations.

www.ti.com
IMPORTANT NOTICE AND DISCLAIMER
TI PROVIDES TECHNICAL AND RELIABILITY DATA (INCLUDING DATA SHEETS), DESIGN RESOURCES (INCLUDING REFERENCE
DESIGNS), APPLICATION OR OTHER DESIGN ADVICE, WEB TOOLS, SAFETY INFORMATION, AND OTHER RESOURCES “AS IS”
AND WITH ALL FAULTS, AND DISCLAIMS ALL WARRANTIES, EXPRESS AND IMPLIED, INCLUDING WITHOUT LIMITATION ANY
IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT OF THIRD
PARTY INTELLECTUAL PROPERTY RIGHTS.
These resources are intended for skilled developers designing with TI products. You are solely responsible for (1) selecting the appropriate
TI products for your application, (2) designing, validating and testing your application, and (3) ensuring your application meets applicable
standards, and any other safety, security, regulatory or other requirements.
These resources are subject to change without notice. TI grants you permission to use these resources only for development of an
application that uses the TI products described in the resource. Other reproduction and display of these resources is prohibited. No license
is granted to any other TI intellectual property right or to any third party intellectual property right. TI disclaims responsibility for, and you
will fully indemnify TI and its representatives against, any claims, damages, costs, losses, and liabilities arising out of your use of these
resources.
TI’s products are provided subject to TI’s Terms of Sale or other applicable terms available either on ti.com or provided in conjunction with
such TI products. TI’s provision of these resources does not expand or otherwise alter TI’s applicable warranties or warranty disclaimers for
TI products.
TI objects to and rejects any additional or different terms you may have proposed. IMPORTANT NOTICE

Ads 8318
No ratings yet
Ads 8318
33 pages
Features Description: D D D D D D D D D D D D D D
No ratings yet
Features Description: D D D D D D D D D D D D D D
40 pages
ads8883 具有 18 位、666kSPS 和串行接口的微功耗小型差动输入 SAR ADC
No ratings yet
ads8883 具有 18 位、666kSPS 和串行接口的微功耗小型差动输入 SAR ADC
51 pages
Ads 1255
No ratings yet
Ads 1255
49 pages
Ads 1256
No ratings yet
Ads 1256
45 pages
Ads 1298
No ratings yet
Ads 1298
80 pages
ADS8321
No ratings yet
ADS8321
19 pages
ADS8864
No ratings yet
ADS8864
51 pages
Ads 8363
No ratings yet
Ads 8363
49 pages
Data Sheet Ads1292r
No ratings yet
Data Sheet Ads1292r
69 pages
Ads 1256
100% (2)
Ads 1256
43 pages
16-Bit, 500-Ksps, Serial Interface Micropower, Miniature, Sar Analog-To-Digital Converter
No ratings yet
16-Bit, 500-Ksps, Serial Interface Micropower, Miniature, Sar Analog-To-Digital Converter
35 pages
ADS8598S 18-Bit, 200-kSPS, 8-Channel, Simultaneous-Sampling ADC With Bipolar Inputs On A Single Supply
No ratings yet
ADS8598S 18-Bit, 200-kSPS, 8-Channel, Simultaneous-Sampling ADC With Bipolar Inputs On A Single Supply
64 pages
16-Channel, 16-Bit Analog-to-Digital Converter: Features Description
No ratings yet
16-Channel, 16-Bit Analog-to-Digital Converter: Features Description
52 pages
Ads8344 16bit 8ch 100KHz
No ratings yet
Ads8344 16bit 8ch 100KHz
27 pages
Ads 8344
No ratings yet
Ads 8344
26 pages
Ads 8668
No ratings yet
Ads 8668
81 pages
Ads 5295
No ratings yet
Ads 5295
93 pages
Ads 1605
No ratings yet
Ads 1605
39 pages
Ads 8860
No ratings yet
Ads 8860
53 pages
ADS9813: 18-Bit 8-Channel ADC Guide
No ratings yet
ADS9813: 18-Bit 8-Channel ADC Guide
55 pages
Ads 9811
No ratings yet
Ads 9811
66 pages
Ads 1194
No ratings yet
Ads 1194
76 pages
Features Description: Sbas020D - January 1996 - Revised October 2006
No ratings yet
Features Description: Sbas020D - January 1996 - Revised October 2006
20 pages
Ads 7805
No ratings yet
Ads 7805
21 pages
ADS1258 16 Channels 24 Bit TI
No ratings yet
ADS1258 16 Channels 24 Bit TI
54 pages
Ads 1258
No ratings yet
Ads 1258
54 pages
Ads 7822
No ratings yet
Ads 7822
28 pages
Ads 7822
No ratings yet
Ads 7822
30 pages
Ads 7846
No ratings yet
Ads 7846
22 pages
Features Description: Sbas125H - September 1999 - Revised January 2005
No ratings yet
Features Description: Sbas125H - September 1999 - Revised January 2005
32 pages
Features Description: Sbas090B - September 2000 - Revised May 2002
No ratings yet
Features Description: Sbas090B - September 2000 - Revised May 2002
17 pages
触摸控制芯片ADS7843英文
No ratings yet
触摸控制芯片ADS7843英文
14 pages
ADS1100
No ratings yet
ADS1100
23 pages
Low-Power, 2-Channel, 24-Bit Analog Front-End For Biopotential Measurements
No ratings yet
Low-Power, 2-Channel, 24-Bit Analog Front-End For Biopotential Measurements
74 pages
Ads111X Ultra-Small, Low-Power, I C-Compatible, 860-Sps, 16-Bit Adcs With Internal Reference, Oscillator, and Programmable Comparator
No ratings yet
Ads111X Ultra-Small, Low-Power, I C-Compatible, 860-Sps, 16-Bit Adcs With Internal Reference, Oscillator, and Programmable Comparator
53 pages
Ads8353 q1
No ratings yet
Ads8353 q1
45 pages
Ads 1282
No ratings yet
Ads 1282
54 pages
02 Ads1288
No ratings yet
02 Ads1288
58 pages
High-Resolution Analog-to-Digital Converter: Features Description
No ratings yet
High-Resolution Analog-to-Digital Converter: Features Description
51 pages
Ads 7828
No ratings yet
Ads 7828
18 pages
ADS7828 DataSheet
No ratings yet
ADS7828 DataSheet
22 pages
Ads 7828
No ratings yet
Ads 7828
23 pages
ADS7828 Datasheet PDF
No ratings yet
ADS7828 Datasheet PDF
23 pages
Ads1234-24 BITS
No ratings yet
Ads1234-24 BITS
39 pages
24-Bit Analog-to-Digital Converter For Bridge Sensors: Features Description
No ratings yet
24-Bit Analog-to-Digital Converter For Bridge Sensors: Features Description
37 pages
Precision ADCs for Bridge Sensors
No ratings yet
Precision ADCs for Bridge Sensors
34 pages
ADS1232IPWR Datasheet
No ratings yet
ADS1232IPWR Datasheet
40 pages
PDF Ads1232-4
No ratings yet
PDF Ads1232-4
38 pages
Ads 1245
No ratings yet
Ads 1245
21 pages
Ultra-Small, Low-Power, 12-Bit Analog-to-Digital Converter With Internal Reference
No ratings yet
Ultra-Small, Low-Power, 12-Bit Analog-to-Digital Converter With Internal Reference
34 pages
Datasheet Ads1115
No ratings yet
Datasheet Ads1115
34 pages
Ads1119 PDF
No ratings yet
Ads1119 PDF
47 pages
Ads 9226
No ratings yet
Ads 9226
37 pages
Ads 1115
No ratings yet
Ads 1115
50 pages
304 hw2
No ratings yet
304 hw2
1 page
Process Control Anshika
No ratings yet
Process Control Anshika
39 pages
Peavey 6505 SCH
No ratings yet
Peavey 6505 SCH
8 pages
THe Surface Polarization Effects in High Efficiency Silicon Solar Cells
No ratings yet
THe Surface Polarization Effects in High Efficiency Silicon Solar Cells
4 pages
Onan BGM NHM Marquis Parts Manual
100% (1)
Onan BGM NHM Marquis Parts Manual
65 pages
Application Note D15 Supertex Understanding MOSFET Data
No ratings yet
Application Note D15 Supertex Understanding MOSFET Data
8 pages
VPX BP Ref Sheet Rev1 051612
No ratings yet
VPX BP Ref Sheet Rev1 051612
10 pages
Tirak: For Man-Riding
80% (5)
Tirak: For Man-Riding
36 pages
WorldofTrade.com B2B Platform Overview
50% (6)
WorldofTrade.com B2B Platform Overview
16 pages
Tubitak Ume Product Catalog 2
No ratings yet
Tubitak Ume Product Catalog 2
55 pages
Lxm32a Manual v100 en PDF
No ratings yet
Lxm32a Manual v100 en PDF
360 pages
RET670 Test Report Differential
50% (2)
RET670 Test Report Differential
3 pages
Research Groups - Final (13MAY22)
No ratings yet
Research Groups - Final (13MAY22)
13 pages
A 4.596 GHZ, High Slew Rate, Ultra Low Power
No ratings yet
A 4.596 GHZ, High Slew Rate, Ultra Low Power
6 pages
Activision/Vivendi Games Merger: by Flavio A. Longato Almudena Guerrero Candel
No ratings yet
Activision/Vivendi Games Merger: by Flavio A. Longato Almudena Guerrero Candel
23 pages
1972 Signetics PLL Applications PDF
No ratings yet
1972 Signetics PLL Applications PDF
82 pages
Power and Distribution Transformer
No ratings yet
Power and Distribution Transformer
7 pages
SIMULINK Model of A Quarter-Vehicle With An Anti-Lock Braking System
No ratings yet
SIMULINK Model of A Quarter-Vehicle With An Anti-Lock Braking System
133 pages
FWSM Boot Failure
No ratings yet
FWSM Boot Failure
4 pages
Toshiba Storage Device Division 3.5-Inch Enterprise HDD SATA INSTALLATION NOTES - 15.0mm Case Height Designs
No ratings yet
Toshiba Storage Device Division 3.5-Inch Enterprise HDD SATA INSTALLATION NOTES - 15.0mm Case Height Designs
2 pages
BJT Differential Amplifier Lab Analysis
No ratings yet
BJT Differential Amplifier Lab Analysis
13 pages
Etech Lab-1-15
No ratings yet
Etech Lab-1-15
15 pages
Ericsson DT 260 Manual PDF
No ratings yet
Ericsson DT 260 Manual PDF
127 pages
Differential Protection
No ratings yet
Differential Protection
3 pages
F02405 - 1 Access MDS Digital Central Unit
No ratings yet
F02405 - 1 Access MDS Digital Central Unit
3 pages
ST6000 Inboard Service Manual
No ratings yet
ST6000 Inboard Service Manual
214 pages
Manual de Servicio Impact 754
No ratings yet
Manual de Servicio Impact 754
142 pages
AF09-30-10-13 Contactor Specs
No ratings yet
AF09-30-10-13 Contactor Specs
5 pages
Lincoln Town Car 1995-1997 Manual de Piezas Full
0% (1)
Lincoln Town Car 1995-1997 Manual de Piezas Full
98 pages
Tinyswitch Plus: Energy Efficient, Low Power Off-Line Switcher
No ratings yet
Tinyswitch Plus: Energy Efficient, Low Power Off-Line Switcher
20 pages