®

ICL7106, ICL7107, ICL7107S

Data Sheet September 15, 2005 FN3082.7

3 1/2 Digit, LCD/LED Display, A/D Features

Converters • Guaranteed Zero Reading for 0V Input on All Scales
The Intersil ICL7106 and ICL7107 are high performance, low
• True Polarity at Zero for Precise Null Detection
power, 31/2 digit A/D converters. Included are seven
segment decoders, display drivers, a reference, and a clock. • 1pA Typical Input Current
The ICL7106 is designed to interface with a liquid crystal • True Differential Input and Reference, Direct Display Drive
display (LCD) and includes a multiplexed backplane drive; - LCD ICL7106, LED lCL7107
the ICL7107 will directly drive an instrument size light
emitting diode (LED) display. • Low Noise - Less Than 15µVP-P

The ICL7106 and ICL7107 bring together a combination of • On Chip Clock and Reference
high accuracy, versatility, and true economy. It features auto- • Low Power Dissipation - Typically Less Than 10mW
zero to less than 10µV, zero drift of less than 1µV/oC, input
• No Additional Active Circuits Required
bias current of 10pA (Max), and rollover error of less than
one count. True differential inputs and reference are useful in • Enhanced Display Stability
all systems, but give the designer an uncommon advantage • Pb-Free Plus Anneal Available (RoHS Compliant)
when measuring load cells, strain gauges and other bridge
type transducers. Finally, the true economy of single power
supply operation (ICL7106), enables a high performance
panel meter to be built with the addition of only 10 passive
components and a display.

Ordering Information
TEMP. RANGE
PART NO. PART MARKING (°C) PACKAGE PKG. DWG. #
ICL7106CPL ICL7106CPL 0 to 70 40 Ld PDIP E40.6
ICL7106CPLZ (Note 2) ICL7106CPLZ 0 to 70 40 Ld PDIP(Pb-free) (Note 3) E40.6
ICL7106CM44 ICL7106CM44 0 to 70 44 Ld MQFP Q44.10x10
ICL7106CM44Z (Note 2) ICL7106CM44Z 0 to 70 44 Ld MQFP (Pb-free) Q44.10x10
ICL7106CM44ZT (Note 2) ICL7106CM44Z 0 to 70 44 Ld MQFP Tape and Reel (Pb-free) Q44.10x10
ICL7107CPL ICL7107CPL 0 to 70 40 Ld PDIP E40.6
ICL7107CPLZ (Note 2) ICL7107CPLZ 0 to 70 40 Ld PDIP(Pb-free) (Note 3) E40.6
ICL7107RCPL ICL7107RCPL 0 to 70 40 Ld PDIP (Note 1) E40.6
ICL7107RCPLZ (Note 2) ICL7107RCPLZ 0 to 70 40 Ld PDIP (Pb-free) (Notes 1, 3) E40.6
ICL7107SCPL ICL7107SCPL 0 to 70 40 Ld PDIP (Notes 1, 3) E40.6
ICL7107SCPLZ (Note 2) ICL7107SCPLZ 0 to 70 40 Ld PDIP (Pb-free) (Notes 1, 3) E40.6
ICL7107CM44 ICL7107CM44 0 to 70 44 Ld MQFP Q44.10x10
ICL7107CM44T ICL7107CM44 0 to 70 44 Ld MQFP Tape and Reel Q44.10x10
ICL7107CM44Z (Note 2) ICL7107CM44Z 0 to 70 44 Ld MQFP (Pb-free) Q44.10x10
ICL7107CM44ZT (Note 2) ICL7107CM44Z 0 to 70 44 Ld MQFP Tape and Reel (Pb-free) Q44.10x10
NOTES:
1. “R” indicates device with reversed leads for mounting to PC board underside. “S” indicates enhanced stability.
2. Intersil Pb-free plus anneal products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate
termination finish, which are RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are
MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
3. Pb-free PDIPs can be used for through hole wave solder processing only. They are not intended for use in Reflow solder processing applications.

1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright Intersil Americas Inc. 2002, 2004, 2005. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
 ICL7106, ICL7107, ICL7107S

Pinouts
ICL7106, ICL7107 (PDIP) ICL7107R (PDIP)
TOP VIEW TOP VIEW

V+ 1 40 OSC 1
OSC 1 1 40 V+
D1 2 39 OSC 2
OSC 2 2 39 D1
C1 3 38 OSC 3
OSC 3 3 38 C1
B1 4 37 TEST
TEST 4 37 B1
(1’s) A1 5 36 REF HI
REF HI 5 36 A1 (1’s)
F1 6 35 REF LO
REF LO 6 35 F1
G1 7 34 CREF+
CREF+ 7 34 G1
E1 8 33 CREF-
CREF- 8 33 E1
D2 9 32 COMMON
COMMON 9 32 D2
C2 10 31 IN HI
IN HI 10 31 C2
B2 11 30 IN LO
(10’s) IN LO 11 30 B2
A2 12 29 A-Z (10’s)
A-Z 12 29 A2
F2 13 28 BUFF
BUFF 13 28 F2
E2 14 27 INT
INT 14 27 E2
D3 15 26 V-
V- 15 26 D3
B3 16 25 G2 (10’s)
(100’s) G2 (10’s) 16 25 B3
F3 17 24 C3 (100’s)
C3 17 24 F3
E3 18 23 A3 (100’s)
(100’s) A3 18 23 E3
(1000) AB4 19 22 G3
G3 19 22 (1000) AB4
POL 20 21 BP/GND
(MINUS) BP/GND 20 21 POL
(MINUS)

ICL7106, ICL7107 (MQFP)

TOP VIEW
COMMON
REF LO
REF HI

CREF+
CREF-

IN LO

BUFF
IN HI

A-Z

INT
V-

44 43 42 41 40 39 38 37 36 35 34
NC 1 33 NC
NC 2 32 G2
TEST 3 31 C3
OSC 3 4 30 A3
NC 5 29 G3
OSC 2 6 28 BP/GND
OSC 1 7 27 POL
V+ 8 26 AB4
D1 9 25 E3
C1 10 24 F3
B1 11 23 B3
12 13 14 15 16 17 18 19 20 21 22

A1 F1 G1 E1 D2 C2 B2 A2 F2 E2 D3

2 FN3082.7
 ICL7106, ICL7107, ICL7107S

Absolute Maximum Ratings Thermal Information

Supply Voltage Thermal Resistance (Typical, Note 2) θJA (oC/W)
ICL7106, V+ to V- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15V PDIP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
ICL7107, V+ to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6V MQFP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
ICL7107, V- to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -9V Maximum Junction Temperature . . . . . . . . . . . . . . . . . . . . . . .150oC
Analog Input Voltage (Either Input) (Note 1) . . . . . . . . . . . . V+ to V- Maximum Storage Temperature Range . . . . . . . . . . -65oC to 150oC
Reference Input Voltage (Either Input). . . . . . . . . . . . . . . . . V+ to V- Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . .300oC
Clock Input (MQFP - Lead Tips Only)
ICL7106 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TEST to V+
ICL7107 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GND to V+ NOTE: Pb-free PDIPs can be used for through hole wave solder
processing only. They are not intended for use in Reflow solder
Operating Conditions processing applications.
Temperature Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0oC to 70oC

CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.

NOTES:
1. Input voltages may exceed the supply voltages provided the input current is limited to ±100µA.
2. θJA is measured with the component mounted on a low effective thermal conductivity test board in free air. See Tech Brief TB379 for details.

Electrical Specifications (Note 3)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

SYSTEM PERFORMANCE

Zero Input Reading VIN = 0.0V, Full Scale = 200mV -000.0 ±000.0 +000.0 Digital
Reading

Stability (Last Digit) (ICL7106S, ICL7107S Fixed Input Voltage (Note 6) -000.0 ±000.0 +000.0 Digital
Only) Reading

Ratiometric Reading VlN = VREF , VREF = 100mV 999 999/10 1000 Digital
00 Reading

Rollover Error -VIN = +VlN ≅ 200mV - ±0.2 ±1 Counts

Difference in Reading for Equal Positive and Negative
Inputs Near Full Scale
Linearity Full Scale = 200mV or Full Scale = 2V Maximum - ±0.2 ±1 Counts
Deviation from Best Straight Line Fit (Note 5)

Common Mode Rejection Ratio VCM = 1V, VIN = 0V, Full Scale = 200mV (Note 5) - 50 - µV/V
Noise VIN = 0V, Full Scale = 200mV - 15 - µV
(Peak-To-Peak Value Not Exceeded 95% of Time)

Leakage Current Input VlN = 0 (Note 5) - 1 10 pA

Zero Reading Drift VlN = 0, 0oC To 70oC (Note 5) - 0.2 1 µV/oC

Scale Factor Temperature Coefficient VIN = 199mV, 0oC To 70oC, - 1 5 ppm/oC

(Ext. Ref. 0ppm/× oC) (Note 5)

End Power Supply Character V+ Supply VIN = 0 (Does Not Include LED Current for ICL7107) - 1.0 1.8 mA
Current

End Power Supply Character V- Supply Current ICL7107 Only - 0.6 1.8 mA

COMMON Pin Analog Common Voltage 25kΩ Between Common and 2.4 3.0 3.2 V
Positive Supply (With Respect to + Supply)

Temperature Coefficient of Analog Common 25kΩ Between Common and - 80 - ppm/oC

Positive Supply (With Respect to + Supply)

DISPLAY DRIVER ICL7106 ONLY

Peak-To-Peak Segment Drive Voltage V+ = to V- = 9V (Note 4) 4 5.5 6 V

Peak-To-Peak Backplane Drive Voltage

3 FN3082.7
 ICL7106, ICL7107, ICL7107S

Electrical Specifications (Note 3) (Continued)

PARAMETER TEST CONDITIONS MIN TYP MAX UNIT

DISPLAY DRIVER ICL7107 ONLY

Segment Sinking Current V+ = 5V, Segment Voltage = 3V

Except Pins 19 and 20 5 8 - mA

Pin 19 Only 10 16 - mA

Pin 20 Only 4 7 - mA

NOTES:
3. Unless otherwise noted, specifications apply to both the ICL7106 and ICL7107 at TA = 25oC, fCLOCK = 48kHz. ICL7106 is tested in the circuit
of Figure 1. ICL7107 is tested in the circuit of Figure 2.
4. Back plane drive is in phase with segment drive for “off” segment, 180 degrees out of phase for “on” segment. Frequency is 20 times conversion
rate. Average DC component is less than 50mV.
5. Not tested, guaranteed by design.
6. Sample Tested.

Typical Applications and Test Circuits

+ - 9V
IN + -
R1 R5
C5
R4 C1 C2 R2 C3
R3 C4 DISPLAY
C1 = 0.1µF
OSC 1 40
OSC 2 39
OSC 3 38
TEST 37
REF HI 36
REF LO 35
CREF+ 34
CREF- 33
COM 32
IN HI 31
IN LO 30
A-Z 29
BUFF 28
INT 27
V- 26
G2 25
C3 24
A3 23
G3 22
BP 21
C2 = 0.47µF
C3 = 0.22µF
C4 = 100pF
C5 = 0.02µF
R1 = 24kΩ
ICL7106
R2 = 47kΩ
20 POL
19 AB4

R3 = 100kΩ
G1
D1
C1
B1
A1

D2
10 C2
11 B2
12 A2

15 D3
16 B3
V+

E1

14 E2

18 E3
F1

13 F2

17 F3

R4 = 1kΩ
1
2
3
4
5
6
7
8
9

R5 = 1MΩ
DISPLAY

FIGURE 1. ICL7106 TEST CIRCUIT AND TYPICAL APPLICATION WITH LCD DISPLAY COMPONENTS SELECTED FOR 200mV FULL
SCALE

+5V + - -5V
IN

R1 R5
C5
R4 C1 C2 R2 C3
R3 C4 DISPLAY
C1 = 0.1µF
OSC 1 40
OSC 2 39
OSC 3 38
TEST 37
REF HI 36
REF LO 35
CREF+ 34
CREF- 33
COM 32
IN HI 31
IN LO 30
A-Z 29
BUFF 28
INT 27
V- 26
G2 25
C3 24
A3 23
G3 22
GND 21

C2 = 0.47µF
C3 = 0.22µF
C4 = 100pF
C5 = 0.02µF
R1 = 24kΩ
ICL7107 R2 = 47kΩ
20 POL
19 AB4

R3 = 100kΩ
G1
D1
C1
B1
A1

D2
10 C2
11 B2
12 A2

15 D3
16 B3
V+

E1

14 E2

18 E3
F1

13 F2

17 F3

R4 = 1kΩ
1
2
3
4
5
6
7
8
9

R5 = 1MΩ
DISPLAY

FIGURE 2. ICL7107 TEST CIRCUIT AND TYPICAL APPLICATION WITH LED DISPLAY COMPONENTS SELECTED FOR 200mV FULL
SCALE

4 FN3082.7
 ICL7106, ICL7107, ICL7107S

Design Information Summary Sheet

• OSCILLATOR FREQUENCY • DISPLAY COUNT
V IN
fOSC = 0.45/RC COUNT = 1000 × ---------------
V REF
COSC > 50pF; ROSC > 50kΩ
fOSC (Typ) = 48kHz
• CONVERSION CYCLE
• OSCILLATOR PERIOD
tCYC = tCL0CK x 4000
tOSC = RC/0.45 tCYC = tOSC x 16,000
when fOSC = 48kHz; tCYC = 333ms
• INTEGRATION CLOCK FREQUENCY
• COMMON MODE INPUT VOLTAGE
fCLOCK = fOSC/4
(V- + 1V) < VlN < (V+ - 0.5V)
• INTEGRATION PERIOD
• AUTO-ZERO CAPACITOR
tINT = 1000 x (4/fOSC) 0.01µF < CAZ < 1µF
• 60/50Hz REJECTION CRITERION • REFERENCE CAPACITOR
tINT/t60Hz or tlNT/t60Hz = Integer 0.1µF < CREF < 1µF
• OPTIMUM INTEGRATION CURRENT • VCOM
IINT = 4µA Biased between Vi and V-.

• FULL SCALE ANALOG INPUT VOLTAGE • VCOM ≅ V+ - 2.8V

Regulation lost when V+ to V- < ≅6.8V
VlNFS (Typ) = 200mV or 2V
If VCOM is externally pulled down to (V+ to V-)/2,
• INTEGRATE RESISTOR the VCOM circuit will turn off.
V INFS
R INT = ----------------
- • ICL7106 POWER SUPPLY: SINGLE 9V
I INT
V+ - V- = 9V
• INTEGRATE CAPACITOR Digital supply is generated internally
( t INT ) ( I INT ) VGND ≅ V+ - 4.5V
C INT = -------------------------------
-
V INT • ICL7106 DISPLAY: LCD
Type: Direct drive with digital logic supply amplitude.
• INTEGRATOR OUTPUT VOLTAGE SWING
( t INT ) ( I INT ) • ICL7107 POWER SUPPLY: DUAL ±5.0V
V INT = -------------------------------
-
C INT V+ = +5V to GND
V- = -5V to GND
• VINT MAXIMUM SWING: Digital Logic and LED driver supply V+ to GND

(V- + 0.5V) < VINT < (V+ - 0.5V), VINT (Typ) = 2V • ICL7107 DISPLAY: LED
Type: Non-Multiplexed Common Anode

Typical Integrator Amplifier Output Waveform (INT Pin)

AUTO ZERO PHASE SIGNAL INTEGRATE DE-INTEGRATE PHASE

(COUNTS) PHASE FIXED 0 - 1999 COUNTS
2999 - 1000 1000 COUNTS

TOTAL CONVERSION TIME = 4000 x tCLOCK = 16,000 x tOSC

5 FN3082.7
 ICL7106, ICL7107, ICL7107S

Detailed Description output to return to zero is proportional to the input signal.

Specifically the digital reading displayed is:
Analog Section
 V IN 
Figure 3 shows the Analog Section for the ICL7106 and DISPLAY COUNT = 1000  --------------- .
ICL7107. Each measurement cycle is divided into three  V REF
phases. They are (1) auto-zero (A-Z), (2) signal integrate
(INT) and (3) de-integrate (DE). Differential Input
Auto-Zero Phase The input can accept differential voltages anywhere within the
common mode range of the input amplifier, or specifically from
During auto-zero three things happen. First, input high and low
0.5V below the positive supply to 1V above the negative
are disconnected from the pins and internally shorted to analog
supply. In this range, the system has a CMRR of 86dB typical.
COMMON. Second, the reference capacitor is charged to the
However, care must be exercised to assure the integrator
reference voltage. Third, a feedback loop is closed around the
output does not saturate. A worst case condition would be a
system to charge the auto-zero capacitor CAZ to compensate
large positive common mode voltage with a near full scale
for offset voltages in the buffer amplifier, integrator, and
negative differential input voltage. The negative input signal
comparator. Since the comparator is included in the loop, the A-
drives the integrator positive when most of its swing has been
Z accuracy is limited only by the noise of the system. In any
used up by the positive common mode voltage. For these
case, the offset referred to the input is less than 10µV.
critical applications the integrator output swing can be
Signal Integrate Phase reduced to less than the recommended 2V full scale swing
During signal integrate, the auto-zero loop is opened, the with little loss of accuracy. The integrator output can swing to
internal short is removed, and the internal input high and low within 0.3V of either supply without loss of linearity.
are connected to the external pins. The converter then Differential Reference
integrates the differential voltage between IN HI and IN LO for a
The reference voltage can be generated anywhere within the
fixed time. This differential voltage can be within a wide
power supply voltage of the converter. The main source of
common mode range: up to 1V from either supply. If, on the
common mode error is a roll-over voltage caused by the
other hand, the input signal has no return with respect to the
reference capacitor losing or gaining charge to stray capacity
converter power supply, IN LO can be tied to analog COMMON
on its nodes. If there is a large common mode voltage, the
to establish the correct common mode voltage. At the end of
reference capacitor can gain charge (increase voltage) when
this phase, the polarity of the integrated signal is determined.
called up to de-integrate a positive signal but lose charge
De-Integrate Phase (decrease voltage) when called up to de-integrate a negative
The final phase is de-integrate, or reference integrate. Input input signal. This difference in reference for positive or negative
low is internally connected to analog COMMON and input input voltage will give a roll-over error. However, by selecting the
high is connected across the previously charged reference reference capacitor such that it is large enough in comparison
capacitor. Circuitry within the chip ensures that the capacitor to the stray capacitance, this error can be held to less than 0.5
will be connected with the correct polarity to cause the count worst case. (See Component Value Selection.)
integrator output to return to zero. The time required for the
STRAY STRAY
CREF
RINT CAZ CINT
CREF+ REF HI REF LO CREF - BUFFER V+ A-Z INT

V+ 34 36 35 33 28 1 29 27
INTEGRATOR
A-Z A-Z TO
10µA - -
+
-
+ DIGITAL
+ SECTION
31 2.8V
IN HI
INT DE- DE+ INPUT 6.2V A-Z
HIGH

A-Z
COMPARATOR
N -
+
32 DE+ DE-
COMMON
INT A-Z AND DE(±) INPUT
30 LOW
IN LO

V-
FIGURE 3. ANALOG SECTION OF ICL7106 AND ICL7107

6 FN3082.7
 ICL7106, ICL7107, ICL7107S

Analog COMMON V+
This pin is included primarily to set the common mode
voltage for battery operation (ICL7106) or for any system
V
where the input signals are floating with respect to the power
REF HI
supply. The COMMON pin sets a voltage that is
REF LO 6.8V
approximately 2.8V more negative than the positive supply. ZENER
This is selected to give a minimum end-of-life battery voltage
IZ
of about 6V. However, analog COMMON has some of the ICL7106
ICL7107
attributes of a reference voltage. When the total supply
voltage is large enough to cause the zener to regulate (>7V),
the COMMON voltage will have a low voltage coefficient
V-
(0.001%/V), low output impedance (≅15Ω), and a
temperature coefficient typically less than 80ppm/×oC. FIGURE 4A.

The limitations of the on chip reference should also be V+

recognized, however. With the ICL7107, the internal heating
which results from the LED drivers can cause some V 6.8kΩ
degradation in performance. Due to their higher thermal 20kΩ
ICL7106
resistance, plastic parts are poorer in this respect than ICL7107
ceramic. The combination of reference Temperature
REF HI ICL8069
Coefficient (TC), internal chip dissipation, and package
1.2V
thermal resistance can increase noise near full scale from REF LO REFERENCE
25µV to 80µVP-P. Also the linearity in going from a high
COMMON
dissipation count such as 1000 (20 segments on) to a low
dissipation count such as 1111(8 segments on) can suffer by
a count or more. Devices with a positive TC reference may FIGURE 4B.
require several counts to pull out of an over-range condition. FIGURE 4. USING AN EXTERNAL REFERENCE
This is because over-range is a low dissipation mode, with the
three least significant digits blanked. Similarly, units with a TEST
negative TC may cycle between over-range and a non-over- The TEST pin serves two functions. On the ICL7106 it is
range count as the die alternately heats and cools. All these coupled to the internally generated digital supply through a
problems are of course eliminated if an external reference is 500Ω resistor. Thus it can be used as the negative supply for
used. externally generated segment drivers such as decimal points
The ICL7106, with its negligible dissipation, suffers from or any other presentation the user may want to include on
none of these problems. In either case, an external reference the LCD display. Figures 5 and 6 show such an application.
can easily be added, as shown in Figure 4. No more than a 1mA load should be applied.

Analog COMMON is also used as the input low return during

auto-zero and de-integrate. If IN LO is different from analog
V+ 1MΩ
COMMON, a common mode voltage exists in the system
and is taken care of by the excellent CMRR of the converter. TO LCD
However, in some applications IN LO will be set at a fixed DECIMAL
POINT
known voltage (power supply common for instance). In this ICL7106
application, analog COMMON should be tied to the same BP
21
point, thus removing the common mode voltage from the
converter. The same holds true for the reference voltage. If TEST
37 TO LCD
reference can be conveniently tied to analog COMMON, it BACKPLANE
should be since this removes the common mode voltage
FIGURE 5. SIMPLE INVERTER FOR FIXED DECIMAL POINT
from the reference system.

Within the lC, analog COMMON is tied to an N-Channel FET The second function is a “lamp test”. When TEST is pulled
that can sink approximately 30mA of current to hold the high (to V+) all segments will be turned on and the display
voltage 2.8V below the positive supply (when a load is trying should read “1888”. The TEST pin will sink about 15mA
to pull the common line positive). However, there is only under these conditions.
10µA of source current, so COMMON may easily be tied to a CAUTION: In the lamp test mode, the segments have a constant DC
more negative voltage thus overriding the internal reference. voltage (no square-wave). This may burn the LCD display if main-
tained for extended periods.

7 FN3082.7
 ICL7106, ICL7107, ICL7107S

absorb the relative large capacitive currents when the back

V+ plane (BP) voltage is switched. The BP frequency is the
V+ clock frequency divided by 800. For three readings/sec., this
BP
is a 60Hz square wave with a nominal amplitude of 5V. The
segments are driven at the same frequency and amplitude
TO LCD and are in phase with BP when OFF, but out of phase when
ICL7106 DECIMAL DECIMAL
POINT POINTS ON. In all cases negligible DC voltage exists across the
SELECT
segments.
TEST Figure 8 is the Digital Section of the ICL7107. It is identical to
CD4030 the ICL7106 except that the regulated supply and back plane
GND drive have been eliminated and the segment drive has been
increased from 2mA to 8mA, typical for instrument size
FIGURE 6. EXCLUSIVE ‘OR’ GATE FOR DECIMAL POINT DRIVE common anode LED displays. Since the 1000 output (pin 19)
must sink current from two LED segments, it has twice the
drive capability or 16mA.
Digital Section
In both devices, the polarity indication is “on” for negative
Figures 7 and 8 show the digital section for the ICL7106 and
analog inputs. If IN LO and IN HI are reversed, this indication
ICL7107, respectively. In the ICL7106, an internal digital
can be reversed also, if desired.
ground is generated from a 6V Zener diode and a large
P-Channel source follower. This supply is made stiff to

a a a
a f b f b f b
g c g g
e c e c e c
b
d d d
BACKPLANE
21

LCD PHASE DRIVER

7 7 7
TYPICAL SEGMENT OUTPUT
V+
SEGMENT
DECODE
SEGMENT
DECODE
SEGMENT
DECODE
÷200
0.5mA

SEGMENT LATCH
OUTPUT
2mA
1000’s 100’s 10’s 1’s
COUNTER COUNTER COUNTER COUNTER
INTERNAL DIGITAL GROUND

TO SWITCH DRIVERS
FROM COMPARATOR OUTPUT 1
V+
CLOCK
† ÷4 LOGIC CONTROL 6.2V

500Ω
TEST
† THREE INVERTERS INTERNAL 37
ONE INVERTER SHOWN FOR CLARITY DIGITAL VTH = 1V
GROUND
26
V-
40 39 38

OSC 1 OSC 2 OSC 3

FIGURE 7. ICL7106 DIGITAL SECTION

8 FN3082.7
 ICL7106, ICL7107, ICL7107S

a a a
a f b f b f b
g c g g
e c e c e c
b
d d d

7 7 7
SEGMENT SEGMENT SEGMENT
DECODE DECODE DECODE

TYPICAL SEGMENT OUTPUT

V+ LATCH
0.5mA

TO 1000’s 100’s 10’s 1’s

SEGMENT COUNTER COUNTER COUNTER COUNTER
8mA
TO SWITCH DRIVERS
DIGITAL GROUND FROM COMPARATOR OUTPUT 1
V+
V+
CLOCK TEST
† ÷4 LOGIC CONTROL 37
500Ω
† THREE INVERTERS DIGITAL
27 GROUND
ONE INVERTER SHOWN FOR CLARITY
40 39 38

OSC 1 OSC 2 OSC 3

FIGURE 8. ICL7107 DIGITAL SECTION

System Timing
INTERNAL TO PART
Figure 9 shows the clocking arrangement used in the
ICL7106 and ICL7107. Two basic clocking arrangements ÷4 CLOCK
can be used:

1. Figure 9A. An external oscillator connected to pin 40.

2. Figure 9B. An R-C oscillator using all three pins. 40 39 38
The oscillator frequency is divided by four before it clocks the
decade counters. It is then further divided to form the three GND ICL7107
convert-cycle phases. These are signal integrate (1000 TEST ICL7106
counts), reference de-integrate (0 to 2000 counts) and FIGURE 9A.
auto-zero (1000 to 3000 counts). For signals less than full
scale, auto-zero gets the unused portion of reference
de-integrate. This makes a complete measure cycle of 4,000 INTERNAL TO PART
counts (16,000 clock pulses) independent of input voltage. ÷4 CLOCK
For three readings/second, an oscillator frequency of 48kHz
would be used.

To achieve maximum rejection of 60Hz pickup, the signal

40 39 38
integrate cycle should be a multiple of 60Hz. Oscillator
frequencies of 240kHz, 120kHz, 80kHz, 60kHz, 48kHz, C
R
40kHz, 331/3kHz, etc. should be selected. For 50Hz
rejection, Oscillator frequencies of 200kHz, 100kHz, RC OSCILLATOR

662/3kHz, 50kHz, 40kHz, etc. would be suitable. Note that

40kHz (2.5 readings/second) will reject both 50Hz and 60Hz FIGURE 9B.
(also 400Hz and 440Hz). FIGURE 9. CLOCK CIRCUITS

9 FN3082.7
 ICL7106, ICL7107, ICL7107S

Component Value Selection Reference Voltage

The analog input required to generate full scale output (2000
Integrating Resistor
counts) is: VlN = 2VREF. Thus, for the 200mV and 2V scale,
Both the buffer amplifier and the integrator have a class A VREF should equal 100mV and 1V, respectively. However, in
output stage with 100µA of quiescent current. They can many applications where the A/D is connected to a
supply 4µA of drive current with negligible nonlinearity. The transducer, there will exist a scale factor other than unity
integrating resistor should be large enough to remain in this between the input voltage and the digital reading. For
very linear region over the input voltage range, but small instance, in a weighing system, the designer might like to
enough that undue leakage requirements are not placed on have a full scale reading when the voltage from the
the PC board. For 2V full scale, 470kΩ is near optimum and transducer is 0.662V. Instead of dividing the input down to
similarly a 47kΩ for a 200mV scale. 200mV, the designer should use the input voltage directly
Integrating Capacitor and select VREF = 0.341V. Suitable values for integrating
resistor and capacitor would be 120kΩ and 0.22µF. This
The integrating capacitor should be selected to give the
makes the system slightly quieter and also avoids a divider
maximum voltage swing that ensures tolerance buildup will
network on the input. The ICL7107 with ±5V supplies can
not saturate the integrator swing (approximately. 0.3V from
accept input signals up to ±4V. Another advantage of this
either supply). In the ICL7106 or the ICL7107, when the
system occurs when a digital reading of zero is desired for
analog COMMON is used as a reference, a nominal +2V full-
VIN ≠ 0. Temperature and weighing systems with a variable
scale integrator swing is fine. For the ICL7107 with +5V
fare are examples. This offset reading can be conveniently
supplies and analog COMMON tied to supply ground, a
generated by connecting the voltage transducer between IN
±3.5V to +4V swing is nominal. For three readings/second
HI and COMMON and the variable (or fixed) offset voltage
(48kHz clock) nominal values for ClNT are 0.22µF and
between COMMON and IN LO.
0.10µF, respectively. Of course, if different oscillator
frequencies are used, these values should be changed in ICL7107 Power Supplies
inverse proportion to maintain the same output swing. The ICL7107 is designed to work from ±5V supplies.
An additional requirement of the integrating capacitor is that However, if a negative supply is not available, it can be
it must have a low dielectric absorption to prevent roll-over generated from the clock output with 2 diodes, 2 capacitors,
errors. While other types of capacitors are adequate for this and an inexpensive lC. Figure 10 shows this application. See
application, polypropylene capacitors give undetectable ICL7660 data sheet for an alternative.
errors at reasonable cost. In fact, in selected applications no negative supply is
Auto-Zero Capacitor required. The conditions to use a single +5V supply are:
The size of the auto-zero capacitor has some influence on 1. The input signal can be referenced to the center of the
the noise of the system. For 200mV full scale where noise is common mode range of the converter.
very important, a 0.47µF capacitor is recommended. On the 2. The signal is less than ±1.5V.
2V scale, a 0.047µF capacitor increases the speed of 3. An external reference is used.
recovery from overload and is adequate for noise on this
scale.

Reference Capacitor V+

A 0.1µF capacitor gives good results in most applications. CD4009

However, where a large common mode voltage exists (i.e.,
the REF LO pin is not at analog COMMON) and a 200mV V+
OSC 1
scale is used, a larger value is required to prevent roll-over
1N914 +
error. Generally 1µF will hold the roll-over error to 0.5 count OSC 2 10
in this instance. µF
OSC 3 0.047 -
µF
Oscillator Components ICL7107
For all ranges of frequency a 100kΩ resistor is recommended GND 1N914
and the capacitor is selected from the equation: V-

0.45
f = ----------- For 48kHz Clock (3 Readings/sec),
RC V- = 3.3V
C = 100pF.
FIGURE 10. GENERATING NEGATIVE SUPPLY FROM +5V

10 FN3082.7
 ICL7106, ICL7107, ICL7107S

Typical Applications Application Notes

The ICL7106 and ICL7107 may be used in a wide variety of NOTE # DESCRIPTION
configurations. The circuits which follow show some of the
possibilities, and serve to illustrate the exceptional versatility AN016 “Selecting A/D Converters”
of these A/D converters. AN017 “The Integrating A/D Converter”

The following application notes contain very useful AN018 “Do’s and Don’ts of Applying A/D Converters”
information on understanding and applying this part and are AN023 “Low Cost Digital Panel Meter Designs”
available from Intersil Corporation.
AN032 “Understanding the Auto-Zero and Common Mode
Performance of the ICL7136/7/9 Family”

AN046 “Building a Battery-Operated Auto Ranging DVM with the

ICL7106”
AN052 “Tips for Using Single Chip 31/2 Digit A/D Converters”

AN9609 “Overcoming Common Mode Range Issues When Using

Intersil Integrating Converters”

Typical Applications
TO PIN 1 TO PIN 1
OSC 1 40 OSC 1 40
100kΩ 100kΩ
OSC 2 39 OSC 2 39
OSC 3 38 SET VREF OSC 3 38 SET VREF
TEST 37 100pF = 100mV TEST 37 100pF = 100mV
REF HI 36 REF HI 36
REF LO 35 REF LO 35 +5V
CREF 34 1kΩ 22kΩ 1kΩ 22kΩ
CREF 34
0.1µF 0.1µF
CREF 33 CREF 33
COMMON 32 1MΩ COMMON 32 1MΩ
+ +
IN HI 31 IN HI 31
0.01µF IN 0.01µF IN
IN LO 30 IN LO 30
0.47µF - 0.47µF -
A-Z 29 + A-Z 29
47kΩ 47kΩ
BUFF 28 9V BUFF 28
INT 27 - INT 27
0.22µF 0.22µF
V - 26 V - 26 -5V
G2 25 G2 25
C3 24 C3 24
TO DISPLAY TO DISPLAY
A3 23 A3 23
G3 22 G3 22
BP 21 TO BACKPLANE GND 21

Values shown are for 200mV full scale, 3 readings/sec., floating Values shown are for 200mV full scale, 3 readings/sec. IN LO may
supply voltage (9V battery). be tied to either COMMON for inputs floating with respect to
supplies, or GND for single ended inputs. (See discussion under
Analog COMMON).

FIGURE 11. ICL7106 USING THE INTERNAL REFERENCE FIGURE 12. ICL7107 USING THE INTERNAL REFERENCE

11 FN3082.7
 ICL7106, ICL7107, ICL7107S

Typical Applications (Continued)

TO PIN 1 TO PIN 1
OSC 1 40 OSC 1 40
100kΩ 100kΩ
OSC 2 39 OSC 2 39
OSC 3 38 SET VREF OSC 3 38 SET VREF
TEST 37 100pF = 100mV 100pF
TEST 37 = 100mV
REF HI 36 REF HI 36
REF LO 35 V+ REF LO 35 +5V
1kΩ 10kΩ 10kΩ 1kΩ 100kΩ
CREF 34 CREF 34
0.1µF 0.1µF 6.8V
CREF 33 1.2V (ICL8069) CREF 33
COMMON 32 1MΩ COMMON 32 1MΩ
+ +
IN HI 31 IN HI 31
0.01µF IN 0.01µF IN
IN LO 30 IN LO 30
0.47µF - 0.47µF -
A-Z 29 A-Z 29
47kΩ 47kΩ
BUFF 28 BUFF 28
INT 27 INT 27
0.22µF 0.22µF
V - 26 V- V - 26 -5V
G2 25 G2 25
C3 24 C3 24
TO DISPLAY TO DISPLAY
A3 23 A3 23
G3 22 G3 22
GND 21 GND 21

IN LO is tied to supply COMMON establishing the correct common mode Since low TC zeners have breakdown voltages ~ 6.8V, diode must
voltage. If COMMON is not shorted to GND, the input voltage may float be placed across the total supply (10V). As in the case of Figure 12,
with respect to the power supply and COMMON acts as a pre-regulator IN LO may be tied to either COMMON or GND.
for the reference. If COMMON is shorted to GND, the input is single
ended (referred to supply GND) and the pre-regulator is overridden.
FIGURE 13. ICL7107 WITH AN EXTERNAL BAND-GAP FIGURE 14. ICL7107 WITH ZENER DIODE REFERENCE
REFERENCE (1.2V TYPE)
TO PIN 1 TO PIN 1
OSC 1 40 OSC 1 40
100kΩ 100kΩ
OSC 2 39 OSC 2 39
OSC 3 38 SET VREF OSC 3 38 SET VREF
TEST 37 100pF = 1V TEST 37 100pF = 100mV
REF HI 36 REF HI 36
REF LO 35 V+ REF LO 35 +5V
25kΩ 24kΩ 1kΩ 10kΩ 15kΩ
CREF 34 CREF 34
0.1µF 0.1µF
CREF 33 CREF 33 1.2V (ICL8069)
COMMON 32 COMMON 32 1MΩ
1MΩ +
+
IN HI 31
IN HI 31 0.01µF IN
0.01µF IN IN LO 30
IN LO 30 0.47µF -
0.047µF - A-Z 29
A-Z 29 47kΩ
470kΩ BUFF 28
BUFF 28
INT 27
INT 27 0.22µF
0.22µF V - 26
V - 26 V-
G2 25
G2 25
C3 24
C3 24 TO DISPLAY
TO DISPLAY A3 23
A3 23 G3 22
G3 22 GND 21
BP/GND 21

An external reference must be used in this application, since the

voltage between V+ and V- is insufficient for correct operation of the
internal reference.
FIGURE 15. ICL7106 AND ICL7107: RECOMMENDED
FIGURE 16. ICL7107 OPERATED FROM SINGLE +5V
COMPONENT VALUES FOR 2V FULL SCALE

12 FN3082.7
 ICL7106, ICL7107, ICL7107S

Typical Applications (Continued)

TO PIN 1 V+ TO PIN 1
OSC 1 40 OSC 1 40
100kΩ 100kΩ
OSC 2 39 OSC 2 39
OSC 3 38 OSC 3 38
100pF SCALE
TEST 37 100pF TEST 37 FACTOR
ADJUST
REF HI 36 REF HI 36
REF LO 35 REF LO 35 22kΩ
CREF 34 100kΩ 1MΩ
CREF 34
0.1µF 0.1µF 100kΩ 220kΩ
CREF 33 CREF 33
COMMON 32 COMMON 32
IN HI 31 IN HI 31 ZERO SILICON NPN
0.01µF ADJUST MPS 3704 OR
IN LO 30 IN LO 30
0.47µF 0.47µF SIMILAR
A-Z 29 A-Z 29
47kΩ 47kΩ
BUFF 28 BUFF 28 9V
INT 27 INT 27
0.22µF 0.22µF
V - 26 V - 26
G2 25 G2 25
C3 24 C3 24
TO DISPLAY TO DISPLAY
A3 23 A3 23
G3 22 G3 22
GND 21 BP 21 TO BACKPLANE

A silicon diode-connected transistor has a temperature coefficient of

The resistor values within the bridge are determined by the desired about -2mV/oC. Calibration is achieved by placing the sensing
sensitivity. transistor in ice water and adjusting the zeroing potentiometer for a
000.0 reading. The sensor should then be placed in boiling water
and the scale-factor potentiometer adjusted for a 100.0 reading.
FIGURE 17. ICL7107 MEASUREING RATIOMETRIC VALUES FIGURE 18. ICL7106 USED AS A DIGITAL CENTIGRADE
OF QUAD LOAD CELL THERMOMETER
V+ +5V
1 V+ OSC 1 40 1 V+ OSC 1 40
2 D1 OSC 2 39 2 D1 OSC 2 39
TO LOGIC 3 C1 OSC 3 38 3 C1 OSC 3 38
VCC
4 B1 TEST 37 4 B1 TEST 37
5 A1 REF HI 36 5 A1 REF HI 36
6 F1 REF LO 35 6 F1 REF LO 35
TO TO LOGIC
7 G1 CREF 34 LOGIC VCC 7 G1 CREF 34
GND
8 E1 CREF 33 8 E1 CREF 33
9 D2 COMMON 32 12kΩ 9 D2 COMMON 32
10 C2 IN HI 31 The LM339 is required to 10 C2 IN HI 31
11 B2 IN LO 30 ensure logic compatibility 11 B2 IN LO 30
12 A2 A-Z 29 with heavy display loading. 12 A2 A-Z 29
13 F2 BUFF 28 LM339 13 F2 BUFF 28
14 E2 INT 27 14 E2 INT 27
+
15 D3 V- 26 V-
- 15 D3 V- 26 V-
16 B3 G2 25 16 B3 G2 25
O/RANGE +
17 F3 C3 24 - 17 F3 C3 24
O/RANGE 18 E3 A3 23 18 E3 A3 23
+
19 AB4 G3 22 - 19 AB4 G3 22
20 POL BP 21 U/RANGE 20 POL BP 21
-
U/RANGE +
CD4023 OR
74C10
33kΩ
CD4023 OR
74C10 CD4077

FIGURE 19. CIRCUIT FOR DEVELOPING UNDERRANGE AND FIGURE 20. CIRCUIT FOR DEVELOPING UNDERRANGE AND
OVERRANGE SIGNAL FROM ICL7106 OUTPUTS OVERRANGE SIGNALS FROM ICL7107 OUTPUT

13 FN3082.7
 ICL7106, ICL7107, ICL7107S

Typical Applications (Continued)

TO PIN 1
OSC 1 40
100kΩ
OSC 2 39 10µF SCALE FACTOR ADJUST
OSC 3 38 (VREF = 100mV FOR AC TO RMS)
100pF CA3140 100kΩ
TEST 37 5µF
+
REF HI 36 AC IN
-
REF LO 35 1N914
1kΩ 22kΩ 470kΩ
CREF 34
0.1µF 2.2MΩ
CREF 33
COMMON 32 1µF 10kΩ 1µF 10kΩ 1µF
IN HI 31
4.3kΩ
IN LO 30
0.47µF 0.22µF
A-Z 29
47kΩ +
BUFF 28 10µF 9V 100pF
INT 27 - (FOR OPTIMUM BANDWIDTH)
0.22µF
V - 26
G2 25
C3 24
TO DISPLAY
A3 23
G3 22
BP 21 TO BACKPLANE

Test is used as a common-mode reference level to ensure compatibility with most op amps.

FIGURE 21. AC TO DC CONVERTER WITH ICL7106

+5V

DM7407 LED
SEGMENTS
ICL7107 130Ω

130Ω

130Ω

FIGURE 22. DISPLAY BUFFERING FOR INCREASED DRIVE CURRENT

14 FN3082.7
 ICL7106, ICL7107, ICL7107S

Dual-In-Line Plastic Packages (PDIP)

E40.6 (JEDEC MS-011-AC ISSUE B)
N 40 LEAD DUAL-IN-LINE PLASTIC PACKAGE
E1
INDEX INCHES MILLIMETERS
AREA 1 2 3 N/2
SYMBOL MIN MAX MIN MAX NOTES
-B-
A - 0.250 - 6.35 4
-A-
D E A1 0.015 - 0.39 - 4
BASE A2 0.125 0.195 3.18 4.95 -
PLANE A2
-C- A B 0.014 0.022 0.356 0.558 -
SEATING
PLANE L C
L
B1 0.030 0.070 0.77 1.77 8
D1 A1 eA C 0.008 0.015 0.204 0.381 -
D1
B1 e D 1.980 2.095 50.3 53.2 5
eC C
B
eB D1 0.005 - 0.13 - 5
0.010 (0.25) M C A B S
E 0.600 0.625 15.24 15.87 6
NOTES: E1 0.485 0.580 12.32 14.73 5
1. Controlling Dimensions: INCH. In case of conflict between English e 0.100 BSC 2.54 BSC -
and Metric dimensions, the inch dimensions control.
eA 0.600 BSC 15.24 BSC 6
2. Dimensioning and tolerancing per ANSI Y14.5M-1982.
eB - 0.700 - 17.78 7
3. Symbols are defined in the “MO Series Symbol List” in Section 2.2
of Publication No. 95. L 0.115 0.200 2.93 5.08 4
4. Dimensions A, A1 and L are measured with the package seated in N 40 40 9
JEDEC seating plane gauge GS-3.
Rev. 0 12/93
5. D, D1, and E1 dimensions do not include mold flash or protrusions.
Mold flash or protrusions shall not exceed 0.010 inch (0.25mm).
6. E and eA are measured with the leads constrained to be per-
pendicular to datum -C- .
7. eB and eC are measured at the lead tips with the leads uncon-
strained. eC must be zero or greater.
8. B1 maximum dimensions do not include dambar protrusions. Dam-
bar protrusions shall not exceed 0.010 inch (0.25mm).
9. N is the maximum number of terminal positions.
10. Corner leads (1, N, N/2 and N/2 + 1) for E8.3, E16.3, E18.3, E28.3,
E42.6 will have a B1 dimension of 0.030 - 0.045 inch (0.76 - 1.14mm).

15 FN3082.7
 ICL7106, ICL7107, ICL7107S

Metric Plastic Quad Flatpack Packages (MQFP)

D
D1 Q44.10x10 (JEDEC MS-022AB ISSUE B)
-D- 44 LEAD METRIC PLASTIC QUAD FLATPACK PACKAGE
INCHES MILLIMETERS
SYMBOL MIN MAX MIN MAX NOTES
A - 0.096 - 2.45 -
A1 0.004 0.010 0.10 0.25 -
-A- -B- A2 0.077 0.083 1.95 2.10 -

E E1 b 0.012 0.018 0.30 0.45 6

b1 0.012 0.016 0.30 0.40 -
D 0.515 0.524 13.08 13.32 3
D1 0.389 0.399 9.88 10.12 4, 5
E 0.516 0.523 13.10 13.30 3
e E1 0.390 0.398 9.90 10.10 4, 5
L 0.029 0.040 0.73 1.03 -
PIN 1
N 44 44 7
SEATING e 0.032 BSC 0.80 BSC -
-H-
A PLANE
Rev. 2 4/99
NOTES:
0.076
0.003 1. Controlling dimension: MILLIMETER. Converted inch
12o-16o -C- dimensions are not necessarily exact.
0.40 0.20 2. All dimensions and tolerances per ANSI Y14.5M-1982.
0.016 MIN 0.008
M C A-B S D S

0o MIN 3. Dimensions D and E to be determined at seating plane -C- .

b
A2 A1 4. Dimensions D1 and E1 to be determined at datum plane
0o-7o b1 -H- .
5. Dimensions D1 and E1 do not include mold protrusion.
0.13/0.17 Allowable protrusion is 0.25mm (0.010 inch) per side.
0.005/0.007
12o-16o 6. Dimension b does not include dambar protrusion. Allowable
L
dambar protrusion shall be 0.08mm (0.003 inch) total.
BASE METAL
7. “N” is the number of terminal positions.
WITH PLATING
0.13/0.23
0.005/0.009

All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.
Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.

For information regarding Intersil Corporation and its products, see www.intersil.com

16 FN3082.7