REF3012, REF3020, REF3025, REF3030, REF3033, REF3040

SBVS032I – MARCH 2002 – REVISED JULY 2022

REF30xx 50-ppm/°C Max, 50-μA, CMOS Voltage Reference in SOT-23-3

1 Features 3 Description
• microSize Package: SOT-23-3 The REF30xx is a precision, low-power, low-dropout
• Low Dropout: 1 mV voltage, reference family available in a tiny 3-pin
• High Output Current: 25 mA SOT-23 package. The REF30xx offers excellent
• High Accuracy: 0.2% temperature drift and initial accuracy while operating
• Low IQ: 42 µA (Typical) at a quiescent current of 42 µA (typical).
• Excellent Specified Drift Performance:
The low power consumption and the relatively high
– 50 ppm/°C (Maximum) From 0°C to 70°C precision make the REF30xx very attractive for loop-
– 75 ppm/°C (Maximum) From –40°C to +125°C powered industrial applications such as pressure and
2 Applications temperature transmitter applications. The REF30xx
is easy to use in intrinsically safe and explosion-
• Temperature and Pressure Transmitters proof applications because it does not require a load
• Portable, Battery-Powered Equipment capacitor to be stable. The REF30xx is specified over
• Data Acquisition Systems the extended industrial temperature range of –40°C to
• Medical Equipment +125°C.
• Handheld Test Equipment
The REF30xx operates with supplies within 1 mV of
output voltage under zero-load conditions. Engineers
can use the low dropout, small size, and low power
consumption of the REF30xx in portable and battery-
powered applications.
Device Information
PART NUMBER PACKAGE BODY SIZE (NOM)
REF30xx SOT-23 (3) 2.92 mm × 1.30 mm

350
3.3 V
REF3033 V+

5Ω
GND 300
Dropout Voltage (mV)

+ 1 μF to 250
10 μF

VREF VCC
VS 200
+
0.1 μF 1 μF to 10 μF
ADS7822
150
VIN +In CS Microcontroller

–In DOUT 100

GND DCLOCK
50

Copyright © 2016, Texas Instruments Incorporated 0

0 5 10 15 20 25 30
Typical Application
Load Current (mA)
Dropout Voltage vs Load Current

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
REF3012, REF3020, REF3025, REF3030, REF3033, REF3040
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Table of Contents
1 Features............................................................................1 9 Application and Implementation.................................. 15
2 Applications..................................................................... 1 9.1 Application Information............................................. 15
3 Description.......................................................................1 9.2 Typical Application.................................................... 15
4 Revision History.............................................................. 2 10 Power Supply Recommendations..............................17
5 Device Comparison Table...............................................3 11 Layout........................................................................... 17
6 Pin Configuration and Functions...................................3 11.1 Layout Guidelines................................................... 17
7 Specifications.................................................................. 4 11.2 Layout Example...................................................... 17
7.1 Absolute Maximum Ratings........................................ 4 12 Device and Documentation Support..........................18
7.2 ESD Ratings............................................................... 4 12.1 Documentation Support.......................................... 18
7.3 Recommended Operating Conditions.........................4 12.2 Related Links.......................................................... 18
7.4 Thermal Information....................................................4 12.3 Receiving Notification of Documentation Updates..18
7.5 Electrical Characteristics.............................................5 12.4 Support Resources................................................. 18
7.6 Typical Characteristics................................................ 7 12.5 Trademarks............................................................. 18
8 Detailed Description...................................................... 11 12.6 Electrostatic Discharge Caution..............................18
8.1 Overview................................................................... 11 12.7 Glossary..................................................................18
8.2 Functional Block Diagram......................................... 11 13 Mechanical, Packaging, and Orderable
8.3 Feature Description...................................................11 Information.................................................................... 18
8.4 Device Functional Modes..........................................13

4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision H (February 2018) to Revision I (July 2022) Page
• Updated the numbering format for tables, figures, and cross-references throughout the document..................1

Changes from Revision G (November 2015) to Revision H (February 2018) Page

• Changed section header From: REF33xx (REF3312, REF3318, REF3320, REF3325, REF3330, REF3333)
To: REF30xx (REF3012, REF3020, REF3025, REF3030, REF30333, REF3040) in the Section 7.5 ...............5
• Added turnon settling time TYP value of 120 µs (deleted by mistake in the previous revision) ........................ 5
• Added NOTE to the Section 9 section ............................................................................................................. 15

Changes from Revision F (August 2008) to Revision G (November 2015) Page

• Added Device Information, ESD Ratings, Recommended Operating Conditions, and Thermal Information
tables.................................................................................................................................................................. 1
• Added Detailed Description, Applications and Implementation, Power-Supply Recommendations, Layout,
Device and Documentation Support, and Mechanical, Packaging, and Orderable Information sections...........1
• Changed text in Description section .................................................................................................................. 1
• Deleted thermal resistance parameter in Electrical Characteristics; see new Thermal Information table.......... 5
• Moved temperature parameters from Electrical Characteristics to Recommended Operating Conditions.........5

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5 Device Comparison Table

PART NUMBER VOLTAGE (V)
REF3012 1.25
REF3020 2.048
REF3025 2.5
REF3030 3.0
REF3033 3.3
REF3040 4.096

6 Pin Configuration and Functions

IN 1

3 GND

OUT 2

Not to scale

Figure 6-1. DBZ Package 3-Pin SOT-23 Top View

Table 6-1. Pin Functions

PIN
I/O DESCRIPTION
NO. NAME
1 IN Input Input supply voltage
2 OUT Output Reference output voltage
3 GND — Ground

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7 Specifications
7.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)(1)
MIN MAX UNIT
Supply voltage, V+ to V– 7.0 V
Output short-circuit current(2) Continuous
Operating temperature –40 125 °C
Junction temperature 150 °C
Storage temperature, 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, which do not imply functional operation of the device at these or any other conditions beyond those indicated under
Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device
reliability.
(2) Short circuit to ground.

7.2 ESD Ratings

VALUE UNIT
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±4000
V(ESD) Electrostatic discharge V
Charged-device model (CDM), per JEDEC specification JESD22-C101(2) ±1500

(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

7.3 Recommended Operating Conditions

at TA = 25°C, VIN = 5 V, and ILOAD = 0 mA (unless otherwise noted)
MIN NOM MAX UNIT
VIN Input voltage VREF + 0.05(1) 5.5 V
ILOAD Load current 25 mA
TA Operating temperature –40 125 °C

(1) For IL > 0, see Section 7.6. Minimum supply voltage for REF3012 is 1.8 V .

7.4 Thermal Information

REF30xx
THERMAL METRIC(1) DBZ (SOT-23) UNIT
3 PINS
RθJA Junction-to-ambient thermal resistance 297.3 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 128.5 °C/W
RθJB Junction-to-board thermal resistance 91.7 °C/W
ψJT Junction-to-top characterization parameter 12.8 °C/W
ψJB Junction-to-board characterization parameter 90.3 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance N/A °C/W

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

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7.5 Electrical Characteristics

at TA = 25°C, VIN = 5 V, and ILOAD = 0 mA (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
REF3012 (1.25 V)(1)
VOUT Output voltage 1.2475 1.25 1.2525 V
Initial accuracy 0.2%
f = 0.1 Hz to 10 Hz 14 μVPP
Output voltage noise
f = 10 Hz to 10 kHz 42 µVrms
Line regulation 1.8 V ≤ VIN ≤ 5.5 V 60 190 µV/V
REF3020 (2.048 V)
VOUT Output voltage 2.044 2.048 2.052 V
Initial accuracy 0.2%
f = 0.1 Hz to 10 Hz 23 μVPP
Output voltage noise
f = 10 Hz to 10 kHz 65 µVrms
Line regulation VREF + 50 mV ≤ VIN ≤ 5.5 V 110 290 µV/V
REF3025 (2.5 V)
VOUT Output voltage 2.495 2.50 2.505 V
Initial accuracy 0.2%
f = 0.1 Hz to 10 Hz 28 μVPP
Output voltage noise
f = 10 Hz to 10 kHz 80 µVrms
Line regulation VREF + 50 mV ≤ VIN ≤ 5.5 V 120 325 µV/V
REF3030 (3.0 V)
VOUT Output voltage 2.994 3.0 3.006 V
Initial accuracy 0.2%
f = 0.1 Hz to 10 Hz 33 μVPP
Output voltage noise
f = 10 Hz to 10 kHz 94 µVrms
Line regulation VREF + 50 mV ≤ VIN ≤ 5.5 V 120 375 µV/V
REF3033 (3.3 V)
VOUT Output voltage 3.294 3.30 3.306 V
Initial accuracy 0.2%
f = 0.1 Hz to 10 Hz 36 μVPP
Output voltage noise
f = 10 Hz to 10 kHz 105 µVrms
Line regulation VREF + 50 mV ≤ VIN ≤ 5.5 V 130 400 µV/V
REF3040 (4.096 V)
VOUT Output voltage 4.088 4.096 4.104 V
Initial accuracy 0.2%
f = 0.1 Hz to 10 Hz 45 μVPP
Output voltage noise
f = 10 Hz to 10 kHz 128 µVrms
Line regulation VREF + 50 mV ≤ VIN ≤ 5.5 V 160 410 µV/V

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7.5 Electrical Characteristics (continued)

at TA = 25°C, VIN = 5 V, and ILOAD = 0 mA (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
REF30xx (REF3012, REF3020, REF3025, REF3030, REF30333, REF3040)
0°C ≤ TA ≤ 70°C 20 50
–30°C ≤ TA ≤ +85°C 28 60
dVOUT/dT Output voltage temperature drift(2) ppm/°C
–40°C ≤ TA ≤ +85°C 30 65
–40°C ≤ TA ≤ +125°C 35 75
0000h to 1000h 24
Long-term stability ppm
1000h to 2000h 15
0 mA < ILOAD < 25 mA, VIN = VREF +
ΔVO(ΔIL) Load regulation(3) 3 100 µV/mA
500 mV(1)
dT Thermal hysteresis(4) 25 100 ppm
VIN – VOUT Dropout voltage 1 50 mV
ISC Short-circuit current 45 mA
Turnon settling time To 0.1% with CL = 1 μF 120 µs
POWER SUPPLY
42 50
IQ Quiescent current μA
–40°C ≤ TA ≤ +125°C 59

(1) The minimum supply voltage for the REF3012 is 1.8 V.

(2) Box method used to determine over temperature drift.
(3) Typical value of load regulation reflects measurements using a force and sense contacts; see Section 8.3.6 section.
(4) Thermal hysteresis procedure explained in more detail in Section 8.3.2 section.

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7.6 Typical Characteristics

at TA = 25°C, VIN = 5 V, and REF3025 used for typical characteristics (unless otherwise noted)

50 100
45 90
40 80
35 70
Number of Units

Number of Units
30 60
25 50
20 40
15 30
10 20
5 10
0 0
5 10 15 20 25 30 35 40 45 50 55 60 65 5 10 15 20 25 30 35 40 45 50 55 60 65
Drift (ppm/°C) Drift (ppm/°C)
0°C to 70°C –40°C to +125°C
Figure 7-1. Temperature Drift Figure 7-2. Temperature Drift
2.502 35

2.500 Maximum Load Current (mA) 30

Output Voltage (V)

2.498 25

2.496 20

2.494 15

2.492 10

2.490 5
-40 -20 0 20 40 60 80 100 120 140 -40 -20 0 20 40 60 80 100 120 140
Temperature (°C) Temperature (°C)
Figure 7-3. Output Voltage vs Temperature Figure 7-4. Maximum Load Current vs Temperature
6 60

5 50
Load Regulation (μV/mA)

4 40
IQ (μA)

3 30

2 20

1 10

0 0
-40 -20 0 20 40 60 80 100 120 140 -40 -20 0 20 40 60 80 100 120 140
Temperature (°C) Temperature (°C)
Figure 7-5. Load Regulation vs Temperature Figure 7-6. Quiescent Current vs Temperature

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7.6 Typical Characteristics (continued)

at TA = 25°C, VIN = 5 V, and REF3025 used for typical characteristics (unless otherwise noted)

200 100

150

Output Impedance (dB)

Line Regulation (μV/V)

10

100
1
50

0.1
0

-50 0.01
-40 -20 0 20 40 60 80 100 120 140 1 10 100 1k 10k 100k
Temperature (°C) Frequency (Hz)
Figure 7-7. Line Regulation vs Temperature Figure 7-8. Output Impedance vs Frequency
90 2.500010

80 2.500000

70 Output Voltage (V) 2.499990

60 2.499980
PSRR (dB)

50 2.499970

40 2.499960

30 2.499950

20 2.499940

2.499930
10
2.499920
0
2.5 3 3.5 4 4.5 5 5.5 6
1 10 100 1k 10k 100k
Supply (V)
Frequency (Hz)
Figure 7-9. Power-Supply Rejection Ratio vs Frequency No Load
Figure 7-10. Output Voltage vs Supply Voltage
2.500200 2.500010

2.500100 2.500000
2.500000 2.499990
Output Voltage (V)
Output Voltage (V)

2.499900
2.499980
2.499800
2.499970
2.499700
2.499960
2.499600
2.499950
2.499500

2.499400 2.499940

2.499300 2.499930
2.5 3 3.5 4 4.5 5 5.5 6 0 5 10 15 20 25 30
Supply (V) Load Current (mA)

ILOAD = 25 mA Figure 7-12. Output Voltage vs Load Current

Figure 7-11. Output Voltage vs Supply Voltage

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7.6 Typical Characteristics (continued)

at TA = 25°C, VIN = 5 V, and REF3025 used for typical characteristics (unless otherwise noted)

5 V/div
3 V/div

VIN VIN

1 V/div
VOUT VOUT
1 V/div

40 ms/div 10 ms/div
CL = 0, 3-V startup CL = 0, 5-V startup
Figure 7-13. Step Response Figure 7-14. Step Response
500 mV/div

IL = 1 mA

VIN
IL = 0 mA
20 mV/div
50 mV/div

VOUT VOUT

10 ms/div 10 ms/div
Figure 7-15. Line Transient Response CL = 0
Figure 7-16. 0-mA to 1-mA Load Transient

IL = 5 mA IL = 6 mA
IL = 0 mA IL = 0 mA
20 mV/div

20 mV/div

VOUT VOUT

10 ms/div 40 ms/div
CL = 0 CL = 1 μF
Figure 7-17. 0-mA to 5-mA Load Transient Figure 7-18. 1-mA to 6-mA Load Transient

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7.6 Typical Characteristics (continued)

at TA = 25°C, VIN = 5 V, and REF3025 used for typical characteristics (unless otherwise noted)

IL = 25 mA
IL = 1 mA
20 mV/div

10 mV/div
VOUT

100 ms/div 1.0 s/div

CL = 1 μF Figure 7-20. 0.1-Hz to 10-Hz Noise

Figure 7-19. 1-mA to 25-mA Load Transient

80 80
Absolute Output Voltage Drift (ppm)

Absolute Output Voltage Drift (ppm)

70 70

60 60

50 50

40 40

30 30

20 20

10 10

0 0
0 100 200 300 400 500 600 700 800 900 1000 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000
Time (hours) Time (hours)
Figure 7-21. Long-Term Stability: 0 to 1000 Hours Figure 7-22. Long-Term Stability: 1000 to 2000 Hours
80
Absolute Output Voltage Drift (ppm)

70

60

50

40

30

20

10

0
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Time (hours)
Figure 7-23. Long-Term Stability: 0 to 2000 Hours

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8 Detailed Description
8.1 Overview
The REF30xx is a series, CMOS, precision bandgap voltage reference. Its basic topology is shown in the
Section 8.2 section. Transistors Q1 and Q2 are biased so that the current density of Q1 is greater than that of
Q2. The difference of the two base-emitter voltages, Vbe1 – Vbe2, has a positive temperature coefficient and
is forced across resistor R1. This voltage is gained up and added to the base-emitter voltage of Q2, which
has a negative coefficient. The resulting output voltage is virtually independent of temperature. The curvature
of the bandgap voltage, as shown in Figure 7-3, is due to the slightly nonlinear temperature coefficient of the
base-emitter voltage of Q2.
8.2 Functional Block Diagram

R1
+ +
Vbe1 Vbe2

Q1 Q2

Copyright © 2016, Texas Instruments Incorporated

8.3 Feature Description

8.3.1 Supply Voltage
The REF30xx family of references features an extremely low dropout voltage. With the exception of the
REF3012, which has a minimum supply requirement of 1.8 V, the REF30xx can be operated with a supply
of only 1 mV above the output voltage in an unloaded condition. For loaded conditions, a typical dropout voltage
versus load is shown on the front page.
The REF30xx features a low quiescent current that is extremely stable over changes in both temperature and
supply. The typical room temperature quiescent current is 42 μA, and the maximum quiescent current over
temperature is just 59 μA. Additionally, the quiescent current typically changes less than 2.5 μA over the entire
supply range, as shown in Figure 8-1.
Supply voltages below the specified levels can cause the REF30xx to momentarily draw currents greater than
the typical quiescent current. Use a power supply with a fast rising edge and low output impedance to easily
prevent this issue.
42.5

42.0

41.5
IQ (μA)

41.0

40.5

40.0
1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6
VIN (V)

Figure 8-1. Supply Current vs Supply Voltage

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8.3.2 Thermal Hysteresis

Thermal hysteresis for the REF30xx is defined as the change in output voltage after operating the device at
25°C, cycling the device through the specified temperature range, and returning to 25°C, and can be expressed
as shown in Equation 1:

æ abs VPRE - VPOST ö 6

VHYST = ç ÷÷ • 10 (ppm)
ç VNOM
è ø (1)

where
• VHYST = Calculated hysteresis
• VPRE = Output voltage measured at 25°C pretemperature cycling
• VPOST = Output voltage measured when device has been operated at 25°C, cycled through specified range of
–40°C to +125°C, and returned to operation at 25°C.
8.3.3 Temperature Drift
The REF30xx exhibits minimal drift error, defined as the change in output voltage over varying temperature.
Using the box method of drift measurement, the REF30xx features a typical drift coefficient of 20 ppm from 0°C
to 70°C, the primary temperature range of use for many applications. For industrial temperature ranges of –40°C
to +125°C, the REF30xx family drift increases to a typical value of 50 ppm.
8.3.4 Noise Performance
The REF30xx generates noise less than 50 μVPP between frequencies of 0.1 Hz to 10 Hz, and can be seen
in Figure 7-20 The noise voltage of the REF30xx increases with output voltage and operating temperature.
Additional filtering may be used to improve output noise levels; however, ensure the output impedance does not
degrade AC performance.
8.3.5 Long-Term Stability
Long-term stability refers to the change of the output voltage of a reference over a period of months or years.
This effect lessens as time progresses as is apparent by the long-term stability curves. The typical drift value for
the REF30xx is 24 ppm from 0 hours to 1000 hours, and 15 ppm from 1000 hours to 2000 hours. This parameter
is characterized by measuring 30 units at regular intervals for a period of 2000 hours.
8.3.6 Load Regulation
Load regulation is defined as the change in output voltage as a result of changes in load current. Load regulation
for the REF30xx is measured using force and sense contacts as shown in Figure 8-2. The force and sense lines
tied to the contact area of the output pin reduce the impact of contact and trace resistance, resulting in accurate
measurement of the load regulation contributed solely by the REF30xx. For applications requiring improved load
regulation, use force and sense lines.

Output Pin
Contact and
Trace Resistance
+
VOUT

IL
Sense Line
Force Line
Load
Meter

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Figure 8-2. Accurate Load Regulation of REF30xx

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8.4 Device Functional Modes

8.4.1 Negative Reference Voltage
For applications requiring a negative and positive reference voltage, the OPA703 and REF30xx can be used
to provide a dual-supply reference from a ±5-V supply. Figure 8-3 shows the REF3025 used to provide a
±2.5-V supply reference voltage. The low offset voltage and low drift of the OPA703 complement the low drift
performance of the REF30xx to provide an accurate solution for split-supply applications.
+5V

REF3025 +2.5 V

10 kW
10 kW

+5 V

OPA703 -2.5 V

-5 V

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Figure 8-3. REF3025 Combined With OPA703 to Create Positive and Negative Reference Voltages.

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8.4.2 Data Acquisition

Often data acquisition systems require stable voltage references to maintain necessary accuracy. The REF30xx
family features stability and a wide range of voltages suitable for most microcontrollers and data converters.
Figure 8-4 and Figure 8-5 show two basic data acquisition systems.

3.3 V
REF3033 V+
GND
5Ω

+ 1 μF to
10 μF

VS
VREF VCC
+
0.1 μF 1 μF to 10 μF
ADS7822

VIN +In CS Microcontroller

–In DOUT

GND DCLOCK

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Figure 8-4. Basic Data Acquisition System 1

2.5-V Supply

5Ω
2.5 V

+
1 μF to 10 μF
VIN

1.25 V VS
REF3012 VOUT VREF VCC
+
0.1 μF ADS8324 1 μF to 10 μF
GND
0 V to 1.25 V +In CS Microcontroller

–In DOUT

GND DCLOCK

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Figure 8-5. Basic Data Acquisition System 2

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9 Application and Implementation

Note
Information in the following applications sections is not part of the TI component specification,
and TI does not warrant its accuracy or completeness. TI’s customers are responsible for
determining suitability of components for their purposes, as well as validating and testing their design
implementation to confirm system functionality.

9.1 Application Information

For normal operation, the REF30xx does not require a capacitor on the output. If a capacitive load is connected,
take special care when using low equivalent series resistance (ESR) capacitors and high capacitance. This
precaution is especially true for low-output voltage devices; therefore, for the REF3012 use a low-ESR
capacitance of 10 μF or less. Figure 9-1 shows the typical connections required for operation of the REF30xx. A
supply bypass capacitor of 0.47 μF is always recommended.

VIN 1
0.47 mF
REF30xx 3

VOUT 2

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Figure 9-1. Typical Connections for Operating REF30xx

9.2 Typical Application

Figure 9-2 shows a low-power reference and conditioning circuit. This circuit attenuates and level-shifts a bipolar
input voltage within the proper input range of a single-supply low power 16-Bit ΔΣ ADC, such as the one inside
the MSP430 or other similar single-supply ADCs. Precision reference circuits are used to level-shift the input
signal, provide the ADC reference voltage and to create a well-regulated supply voltage for the low-power analog
circuitry. A low-power, zero-drift, op-amp circuit is used to attenuate and level-shift the input signal.
3.3 V REF3030 3.0 V
IN OUT

1.25 V
R2

20 k
MSP430F2013
R1 R3 Launchpad
100 k 20 k
+
3.0 V 3.3 V
VOUT
+ J1.2/A1+
+ OPA317 IN+
VIN SD_16
±5 V ± J1.3/A1± A-ADC
VREF

IN±
± R4 R5

100 k 10 k

3.0 V REF3012 1.25 V

J1.5/VREF
IN OUT
R6 0.625 V
47 k

R7
C2
47 k 47 µF

Copyright © 2016, Texas Instruments Incorporated

Figure 9-2. Low-Power Reference and Bipolar Voltage Conditioning Circuit for Low-Power ADCs

Copyright © 2022 Texas Instruments Incorporated Submit Document Feedback 15

Product Folder Links: REF3012 REF3020 REF3025 REF3030 REF3033 REF3040
REF3012, REF3020, REF3025, REF3030, REF3033, REF3040
SBVS032I – MARCH 2002 – REVISED JULY 2022 www.ti.com

9.2.1 Design Requirements

• Supply Voltage: 3.3 V
• Maximum Input Voltage: ±6 V
• Specified Input Voltage: ±5 V
• ADC Reference Voltage: 1.25 V
The goal for this design is to accurately condition a ±5-V bipolar input voltage into a voltage suitable for
conversion by a low-voltage ADC with a 1.25-V reference voltage, VREF, and an input voltage range of VREF / 2.
The circuit should function with reduced performance over a wider input range of at least ±6 V to allow for easier
protection of overvoltage conditions.
9.2.2 Detailed Design Procedure
Figure 9-2 depicts a simplified schematic for this design showing the MSP430 ADC inputs and full input
conditioning circuitry. The ADC is configured for a bipolar measurement where final conversion result is the
differential voltage between the voltage at the positive and negative ADC inputs. The bipolar, GND-referenced
input signal must be level-shifted and attenuated by the op amp so that the output is biased to VREF / 2 and has
a differential voltage that is within the ±VREF / 2 input range of the ADC.
9.2.3 Application Curves

1.25 -0.0001

1 -0.00015
Output Voltage (V)

Error Voltage (V)

0.75 -0.0002

-0.00025
0.5

-0.0003
0.25

-0.00035
0 ±6 ±5 ±4 ±3 ±2 ±1 0 1 2 3 4 5 6
±6 ±5 ±4 ±3 ±2 ±1 0 1 2 3 4 5 6
Input Voltage (V) C00
Input Voltage (V) C001

Figure 9-4. OPA317 Output Voltage Error vs Input

Figure 9-3. OPA317 Output Voltage vs Input
Voltage
Voltage
150

100
Output Code Error (# of codes)

50

±50

±100

±150

±200
±6 ±5 ±4 ±3 ±2 ±1 0 1 2 3 4 5 6
Input Voltage (V) C003

Figure 9-5. Output Code Error vs Input Voltage

16 Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated

Product Folder Links: REF3012 REF3020 REF3025 REF3030 REF3033 REF3040

 REF3012, REF3020, REF3025, REF3030, REF3033, REF3040
www.ti.com SBVS032I – MARCH 2002 – REVISED JULY 2022

10 Power Supply Recommendations

The REF30xx family of references feature an extremely low-dropout voltage. These references can be operated
with a supply of only 50 mV above the output voltage. For loaded reference conditions, a typical dropout voltage
versus load is shown in the front page plot, Figure 3-1. Use a supply bypass capacitor greater than 0.47 µF.
11 Layout
11.1 Layout Guidelines
Figure 11-1 illustrates an example of a printed-circuit board (PCB) layout using the REF30xx. Some key
considerations are:
• Connect low-ESR, 0.1-μF ceramic bypass capacitors at VIN of the REF30xx
• Decouple other active devices in the system per the device specifications
• Use a solid ground plane to help distribute heat and reduces electromagnetic interference (EMI) noise pickup
• Place the external components as close to the device as possible. This configuration prevents parasitic errors
(such as the Seebeck effect) from occurring
• Minimize trace length between the reference and bias connections to the INA and ADC to reduce noise
pickup
• Do not run sensitive analog traces in parallel with digital traces. Avoid crossing digital and analog traces if
possible, and only make perpendicular crossings when absolutely necessary
11.2 Layout Example
To ADC OUT IN To Input Power Supply
C C
REF30xx

GND

Via to Ground Plane

Figure 11-1. Layout Example

Copyright © 2022 Texas Instruments Incorporated Submit Document Feedback 17

Product Folder Links: REF3012 REF3020 REF3025 REF3030 REF3033 REF3040
REF3012, REF3020, REF3025, REF3030, REF3033, REF3040
SBVS032I – MARCH 2002 – REVISED JULY 2022 www.ti.com

12 Device and Documentation Support

12.1 Documentation Support
12.1.1 Related Documentation
CMOS, Rail-to-Rail, I/O Operational Amplifiers (SBOS180)
REF29xx 100 ppm/°C, 50 μA in 3-Pin SOT-23 CMOS Voltage Reference (SBVS033)
12.2 Related Links
Table 12-1 lists quick access links. Categories include technical documents, support and community resources,
tools and software, and quick access to sample or buy.
Table 12-1. Related Links
TECHNICAL TOOLS & SUPPORT &
PARTS PRODUCT FOLDER SAMPLE & BUY
DOCUMENTS SOFTWARE COMMUNITY
REF3012 Click here Click here Click here Click here Click here
REF3020 Click here Click here Click here Click here Click here
REF3025 Click here Click here Click here Click here Click here
REF3030 Click here Click here Click here Click here Click here
REF3033 Click here Click here Click here Click here Click here
REF3040 Click here Click here Click here Click here Click here

12.3 Receiving Notification of Documentation Updates

To receive notification of documentation updates, navigate to the device product folder on ti.com. Click on
Subscribe to updates to register and receive a weekly digest of any product information that has changed. For
change details, review the revision history included in any revised document.
12.4 Support Resources
TI E2E™ support forums are an engineer's go-to source for fast, verified answers and design help — straight
from the experts. Search existing answers or ask your own question to get the quick design help you need.
Linked content is provided "AS IS" by the respective contributors. They do not constitute TI specifications and do
not necessarily reflect TI's views; see TI's Terms of Use.
12.5 Trademarks
TI E2E™ is a trademark of Texas Instruments.
All trademarks are the property of their respective owners.
12.6 Electrostatic Discharge Caution
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.

12.7 Glossary
TI Glossary This glossary lists and explains terms, acronyms, and definitions.

13 Mechanical, Packaging, and Orderable Information

The following pages include mechanical packaging and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.

18 Submit Document Feedback Copyright © 2022 Texas Instruments Incorporated

Product Folder Links: REF3012 REF3020 REF3025 REF3030 REF3033 REF3040

 PACKAGE OPTION ADDENDUM

www.ti.com 13-Jan-2024

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)

REF3012AIDBZR ACTIVE SOT-23 DBZ 3 3000 RoHS & Green NIPDAUAG Level-1-260C-UNLIM -40 to 125 R30A Samples

REF3012AIDBZT ACTIVE SOT-23 DBZ 3 250 RoHS & Green NIPDAUAG Level-1-260C-UNLIM -40 to 125 R30A Samples

REF3020AIDBZR ACTIVE SOT-23 DBZ 3 3000 RoHS & Green NIPDAUAG Level-1-260C-UNLIM -40 to 125 R30B Samples

REF3020AIDBZT ACTIVE SOT-23 DBZ 3 250 RoHS & Green NIPDAUAG Level-1-260C-UNLIM -40 to 125 R30B Samples

REF3025AIDBZR ACTIVE SOT-23 DBZ 3 3000 RoHS & Green NIPDAUAG Level-1-260C-UNLIM -40 to 125 R30C Samples

REF3025AIDBZT ACTIVE SOT-23 DBZ 3 250 RoHS & Green NIPDAUAG Level-1-260C-UNLIM -40 to 125 R30C Samples

REF3030AIDBZR ACTIVE SOT-23 DBZ 3 3000 RoHS & Green NIPDAUAG Level-1-260C-UNLIM -40 to 125 R30F Samples

REF3030AIDBZT ACTIVE SOT-23 DBZ 3 250 RoHS & Green NIPDAUAG Level-1-260C-UNLIM -40 to 125 R30F Samples

REF3033AIDBZR ACTIVE SOT-23 DBZ 3 3000 RoHS & Green NIPDAUAG Level-1-260C-UNLIM -40 to 125 R30D Samples

REF3033AIDBZT ACTIVE SOT-23 DBZ 3 250 RoHS & Green NIPDAUAG Level-1-260C-UNLIM -40 to 125 R30D Samples

REF3040AIDBZR ACTIVE SOT-23 DBZ 3 3000 RoHS & Green NIPDAUAG Level-1-260C-UNLIM -40 to 125 R30E Samples

REF3040AIDBZT ACTIVE SOT-23 DBZ 3 250 RoHS & Green NIPDAUAG Level-1-260C-UNLIM -40 to 125 R30E Samples

(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.

Addendum-Page 1
 PACKAGE OPTION ADDENDUM

www.ti.com 13-Jan-2024

(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
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.

OTHER QUALIFIED VERSIONS OF REF3033 :

• Automotive : REF3033-Q1

NOTE: Qualified Version Definitions:

• Automotive - Q100 devices qualified for high-reliability automotive applications targeting zero defects

Addendum-Page 2
 PACKAGE MATERIALS INFORMATION

www.ti.com 5-Jan-2021

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)
REF3012AIDBZR SOT-23 DBZ 3 3000 179.0 8.4 3.15 2.95 1.22 4.0 8.0 Q3
REF3012AIDBZT SOT-23 DBZ 3 250 179.0 8.4 3.15 2.95 1.22 4.0 8.0 Q3
REF3020AIDBZR SOT-23 DBZ 3 3000 179.0 8.4 3.15 2.95 1.22 4.0 8.0 Q3
REF3020AIDBZT SOT-23 DBZ 3 250 179.0 8.4 3.15 2.95 1.22 4.0 8.0 Q3
REF3025AIDBZR SOT-23 DBZ 3 3000 180.0 8.4 3.15 2.95 1.22 4.0 8.0 Q3
REF3025AIDBZT SOT-23 DBZ 3 250 179.0 8.4 3.15 2.95 1.22 4.0 8.0 Q3
REF3030AIDBZR SOT-23 DBZ 3 3000 179.0 8.4 3.15 2.95 1.22 4.0 8.0 Q3
REF3030AIDBZT SOT-23 DBZ 3 250 179.0 8.4 3.15 2.95 1.22 4.0 8.0 Q3
REF3033AIDBZR SOT-23 DBZ 3 3000 179.0 8.4 3.15 2.95 1.22 4.0 8.0 Q3
REF3033AIDBZT SOT-23 DBZ 3 250 179.0 8.4 3.15 2.95 1.22 4.0 8.0 Q3
REF3040AIDBZR SOT-23 DBZ 3 3000 179.0 8.4 3.15 2.95 1.22 4.0 8.0 Q3
REF3040AIDBZT SOT-23 DBZ 3 250 179.0 8.4 3.15 2.95 1.22 4.0 8.0 Q3

Pack Materials-Page 1
 PACKAGE MATERIALS INFORMATION

www.ti.com 5-Jan-2021

*All dimensions are nominal

Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)
REF3012AIDBZR SOT-23 DBZ 3 3000 200.0 183.0 25.0
REF3012AIDBZT SOT-23 DBZ 3 250 200.0 183.0 25.0
REF3020AIDBZR SOT-23 DBZ 3 3000 200.0 183.0 25.0
REF3020AIDBZT SOT-23 DBZ 3 250 200.0 183.0 25.0
REF3025AIDBZR SOT-23 DBZ 3 3000 200.0 183.0 25.0
REF3025AIDBZT SOT-23 DBZ 3 250 200.0 183.0 25.0
REF3030AIDBZR SOT-23 DBZ 3 3000 200.0 183.0 25.0
REF3030AIDBZT SOT-23 DBZ 3 250 200.0 183.0 25.0
REF3033AIDBZR SOT-23 DBZ 3 3000 200.0 183.0 25.0
REF3033AIDBZT SOT-23 DBZ 3 250 200.0 183.0 25.0
REF3040AIDBZR SOT-23 DBZ 3 3000 200.0 183.0 25.0
REF3040AIDBZT SOT-23 DBZ 3 250 200.0 183.0 25.0

Pack Materials-Page 2
 PACKAGE OUTLINE
DBZ0003A SCALE 4.000
SOT-23 - 1.12 mm max height
SMALL OUTLINE TRANSISTOR

2.64 C
2.10
1.12 MAX
1.4
B A
1.2 0.1 C
PIN 1
INDEX AREA

0.95 (0.125)
3.04
1.9 2.80
3
(0.15)
NOTE 4

2
0.5
3X
0.3
0.2 C A B 4X 0 -15 0.10
(0.95) TYP
0.01

4X 4 -15

0.25
GAGE PLANE 0.20
TYP
0.08

0.6
TYP SEATING PLANE
0 -8 TYP 0.2

4214838/F 08/2024

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. Reference JEDEC registration TO-236, except minimum foot length.
4. Support pin may differ or may not be present.
5. Body dimensions do not include mold flash, protrusions, or gate burrs. Mold flash, protrusions, or gate burrs shall not exceed
0.25mm per side

www.ti.com
 EXAMPLE BOARD LAYOUT
DBZ0003A SOT-23 - 1.12 mm max height
SMALL OUTLINE TRANSISTOR

PKG
3X (1.3)
1

3X (0.6)

SYMM

3
2X (0.95)

(R0.05) TYP
(2.1)

LAND PATTERN EXAMPLE

SCALE:15X

SOLDER MASK
SOLDER MASK METAL METAL UNDER OPENING
OPENING SOLDER MASK

0.07 MAX 0.07 MIN

ALL AROUND ALL AROUND

NON SOLDER MASK SOLDER MASK

DEFINED DEFINED
(PREFERRED)

SOLDER MASK DETAILS

4214838/F 08/2024

NOTES: (continued)

5. Publication IPC-7351 may have alternate designs.

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

www.ti.com
 EXAMPLE STENCIL DESIGN
DBZ0003A SOT-23 - 1.12 mm max height
SMALL OUTLINE TRANSISTOR

PKG

3X (1.3)
1

3X (0.6)

SYMM
3
2X(0.95)

(R0.05) TYP
(2.1)

SOLDER PASTE EXAMPLE

BASED ON 0.125 THICK STENCIL
SCALE:15X

4214838/F 08/2024

NOTES: (continued)

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

www.ti.com
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