Datasheet INA146UA-2K5, INA146UA Datasheet (Burr Brown)

1

®

INA146

®

INA146

©1999 Burr-Brown Corporation PDS-1491A Printed in U.S.A. September, 1999

High-Voltage, Programmable Gain

DIFFERENCE AMPLIFIER

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Twx: 910-952-1111 • Internet: http://www.burr-brown.com/ • Cable: BBRCORP • Telex: 066-6491 • FAX: [phone] • Immediate Product Info: [phone]

For most current data sheet and other product

information, visit www.burr-brown.com

INA146

DESCRIPTION

The INA146 is a precision difference amplifier that
can be used to accurately attenuate high differential
voltages and reject high common-mode voltages for
compatibility with common signal processing voltage
levels. High-voltage capability also affords inherent
input protection. The input common-mode range ex­tends beyond both supply rails, making the INA146
well-suited for both single and dual supply applica­tions.

On-chip precision resistors are laser-trimmed to achieve
accurate gain and high common-mode rejection. Ex­cellent TCR tracking of these resistors assures contin­ued high precision over temperature.

A 10:1 difference amplifier provides 0.1V/V gain
when the output amplifier is used as a unity-gain
buffer. In this configuration, input voltages up to
±100V can be measured. Gains greater than 0.1V/V
can be set with an external resistor pair without affect­ing the common-mode input range.

The INA146 is available in the SO-8 surface-mount
package specified for the extended industrial tempera­ture range, –40°C to +85°C.

FEATURES

● HIGH COMMON-MODE VOLTAGE:

+40V at VS = +5V

±100V at V

S

= ±15V

● DIFFERENTIAL GAIN = 0.1V/V TO 100V/V:

Set with External Resistors

● LOW QUIESCENT CURRENT: 570µA

● WIDE SUPPLY RANGE:

Single Supply: 4.5V to 36V
Dual Supplies: ±2.25V to ±18V

● LOW GAIN ERROR: 0.025%

● HIGH CMR: 80dB

● SO-8 PACKAGE

APPLICATIONS

● CURRENT SHUNT MEASUREMENTS

● SENSOR AMPLIFIER

● SYNCHRONOUS DEMODULATOR

●

CURRENT AND DIFFERENTIAL LINE
RECEIVER

● VOLTAGE-CONTROLLED CURRENT

SOURCE

● BATTERY POWERED SYSTEMS

● LOW COST AUTOMOTIVE

INSTRUMENTATION

R

5

10kΩ

(1%)

A1

V

IN

INA146

V

O

R

2

10kΩ

R

1

100kΩ

V

IN

R

3

100kΩ

R

4

10kΩ

R

G1

R

G2

A2

V

01

RefV–

V+

G = 0.1

+

–

2

5

7

418

6

3

V

O

= (VIN – VIN) 0.1 (1 + RG2/RG1)

+–

2

®

INA146

SPECIFICATIONS: VS = ±2.25V to ±18V Dual Supplies

At TA = +25°C, G = 0.1, RL = 10kΩ connected to ground and ref pin connected to ground unless otherwise noted.

Boldface limits apply over the specified temperature range, T

A

= –40°C to +85°C.

The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes
no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change
without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant
any BURR-BROWN product for use in life support devices and/or systems.

INA146UA
PARAMETER CONDITION MIN TYP MAX UNITS
OFFSET VOLTAGE, V

O

RTI

(1, 2)

Input Offset Voltage V

OS

VS = ±15, V

CM

= VO = 0V ±1 ±5mV

vs Temperature ∆V

OS

/∆T See Typical Curve

vs Power Supply PSRR V

S

= ±1.35V to ±18V ±100 ±600 µV/V
vs Time ±3 µV/mo
Offset Voltage, V

01

RTI

(1, 2)

±1mV

INPUT VOLTAGE RANGE

Common-Mode Voltage Range V

CM

(VIN+) – (VIN–) = 0V, VO = 0V ±100

(3)

V

Common-Mode Rejection CMRR V

CM

= 11 (V–) to 11 (V+) = 11, RS = 0Ω 70 80 dB

Over Temperature 64 74 dB

INPUT BIAS CURRENT

(2)

VCM = VS/2

Bias Current I

B

±50 nA

Offset Current I

OS

±5nA

INPUT IMPEDANCE

Differential (non-inverting input) 110 kΩ
Differential (inverting input) 91.7 kΩ
Common-Mode 55 kΩ

NOISE RTI

(1, 4)

Voltage Noise, f = 0.1Hz to 10Hz 10 µVp-p
Voltage Noise Density, f = 1kHz e

n

550 nV/√Hz

GAIN

G = 0.1 to 100
Gain Equation G = 0.1 • (1 + RG2/RG1)V/V
Initial

(1)

0.1 V/ V

Gain Error R

L

= 100kΩ, VO = (V–)+0.15 to (V+)–1, G = 1 ±0.025 ±0.1 %

vs Temperature R

L

= 100kΩ, VO = (V–)+0.25 to (V+)–1, G = 1 ±1 ±10 ppm/°C

R

L

= 10kΩ, VO = (V–)+0.3 to (V+)–1.25, G = 1 ±0.025 ±0.1 %

vs Temperature R

L

= 10kΩ, VO = (V–)+0.5 to (V+)–1.25, G = 1 ±1 ±10 ppm/°C

Nonlinearity V

O

= (V–)+0.3 to (V+)–1.25, G = 1 ±0.001 ±0.01 % of FS

FREQUENCY RESPONSE

Small Signal Bandwidth G = 0.1 550 kHz

G = 1 50 kHz
Slew Rate 0.45 V/µs
Settling Time, 0.1% G = 1, 10V Step 40 µs

0.01% G = 1, 10V Step 80 µs

Overload Recovery 50% Input Overload 40 µs

OUTPUT, V

O

Voltage Output RL = 100kΩ, G = 1 (V–) + 0.15 (V+) – 1 V

Over Temperature R

L

= 100kΩ, G = 1 (V–) + 0.25 (V+) – 1 V

R

L

= 10kΩ, G = 1 (V–) + 0.3 (V+) – 1.25 V

Over Temperature R

L

= 10kΩ, G = 1 (V–) + 0.5 (V+) – 1.25 V

Short-Circuit Current Continuous to Common ±15 mA
Capacitive Load Stable Operation 1000 pF

POWER SUPPLY

Specified Voltage Range, Dual Supplies ±2.25 ±18 V
Operating Voltage Range ±1.35 ±18 V
Quiescent Current V

IN

= 0, IO = 0 ±570 ±700 µA

Over Temperature

±750 µA

TEMPERATURE RANGE

Specified Range –40 +85 °C
Operating Range –55 +125 °C
Storage Range –55 +125 °C
Thermal Resistance

θ

JA

150 °C/W

NOTES: (1) Overall difference amplifier configuration. Referred to input pins (V

IN

+ and VIN–), gain = 0.1V/V. Specified with 10kΩ in feedback of A2. (2) Input offset
voltage specification includes effects of amplifier’s input bias and offset currents. (3) Common-mode voltage range is 11 (V–) to 11 [(V+) – 1] with a maximum of ±100V.
(4) Includes effects of input current noise and thermal noise contribution of resistor network.

3

®

INA146

SPECIFICATIONS: VS = +5V Single Supply

At TA = +25°C, G = 1, RL = 10kΩ connected to VS/2 and Ref pin connected to VS/2 unless otherwise noted.

Boldface limits apply over the specified temperature range, T

A

= –40°C to +85°C.

INA146UA
PARAMETER CONDITION MIN TYP MAX UNITS
OFFSET VOLTAGE, V

O

RTI

(1, 2)

Input Offset Voltage V

OS

V

CM

= VO = 0V ±3 ±10 mV

vs Temperature ∆V

OS

/∆T See Typical Curve

vs Power Supply Rejection Ratio PSRR V

S

= ±1.35V to ±18V ±100 ±600 µV/°C

vs Time ±3 µV/mo

INPUT VOLTAGE RANGE

Common-Mode Voltage Range V

CM

VIN+ – VIN– = 0V, VO = 0V –25 19 V

Common-Mode Rejection Ratio CMRR V

CM

= –25V to +19V, RS = 0Ω 70 80 dB

Over Temperature 64 74 dB

INPUT BIAS CURRENT

(2)

Bias Current I

B

±50 nA

Offset Current I

OS

±5nA

INPUT IMPEDANCE

Differential (non-inverting input) 110 kΩ
Differential (inverting input) 91.7 kΩ
Common-Mode 55 kΩ

NOISE RTI

(1, 3, 4)

Voltage Noise, f = 0.1Hz to 10Hz 10 µVp-p
Voltage Noise Density, f = 1kHz e

n

550 nV/√Hz

GAIN

G = 0.1 to 100

V/V

Gain Equation G = 0.1 • (1 + R

G2/RG1

)V/V

Initial

(1)

0.1 V/ V

Gain Error R

L

= 100kΩ, VO = 0.15V to 4V, G = 1 ±0.025 ±0.1 %

vs Temperature R

L

= 100kΩ, VO = 0.25V to 4V, G = 1 ±1 ±10 ppm /°C

R

L

= 10kΩ, VO = 0.3V to 3.75V, G = 1 ±0.025 ±0.1 %

vs Temperature R

L

= 10kΩ, VO = 0.5V to 3.75V, G = 1 ±1 ±10 ppm /°C

Nonlinearity V

O

= +0.3 to +3.75, G = 1 ±0.001 ±0.01 % of FS

FREQUENCY RESPONSE

Small Signal Bandwidth G = 0.1 550 kHz

G = 1 50 kHz
Slew Rate 0.45 V/µs
Settling Time, 0.1% G = 1, 10V Step 40 µs

0.01% G = 1, 10V Step 80 µs

Overload Recovery 50% Input Overload 40 µs

OUTPUT, V

O

Voltage Output RL = 100kΩ, G = 1 0.15 4 V

Over Temperature R

L

= 100kΩ, G = 1 0.25 4 V

R

L

= 10kΩ, G = 1 0.3 3.75 V

Over Temperature R

L

= 10kΩ, G = 1 0.5 3.75 V

Short-Circuit Current Continuous to Common ±15 mA
Capacitive Load Stable Operation 1000 pF

POWER SUPPLY

Voltage Range, Dual Supplies ±2.25 ±18 V
Voltage Range, Single Supply ±4.5 ±36 V
Quiescent Current V

IN

= 0, IO = 0 ±570 ±700 µA

Over Temperature

±750 µA

TEMPERATURE RANGE

Specified Range –40 +85 °C
Operating Range –55 +125 °C
Storage Range –55 +125 °C
Thermal Resistance

θ

JA

150 °C/W

NOTES: (1) Overall difference amplifier configuration. Referred to input pins (V

IN

+ and VIN–), gain = 0.1V/V. Specified with 10kΩ in feedback of A2. (2) Input offset
voltage specification includes effects of amplifier’s input bias and offset currents. (3) Includes effects of input current noise and thermal noise contribution of resistor
network. (4) Common-mode voltage range is 11 (V–) to 11 [(V+) – 1] with a maximum of ±100V.

4

®

INA146

AMPLIFIER A1, A2 PERFORMANCE

At TA = +25°C, G = 0.1, RL = 10kΩ connected to ground and Ref pin, unless otherwise noted.

Boldface limits apply over the specified temperature range, T

A

= –40°C to +85°C.

PIN CONFIGURATION

ELECTROSTATIC
DISCHARGE SENSITIVITY

This integrated circuit can be damaged by ESD. Burr-Brown
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.

Supply Voltage, V+ to V– .................................................................... 36V

Signal Input Terminals, Voltage ...................................................... ±100V

Current ....................................................... ±1mA

Output Short Circuit (to ground) .............................................. Continuous

Operating Temperature .................................................. –55°C to +125°C

Storage Temperature ..................................................... –55°C to +150°C

Junction Temperature .................................................................... +150°C

Lead Temperature (soldering, 10s)............................................... +240°C

NOTE: (1) Stresses above these ratings may cause permanent damage.
Exposure to absolute maximum conditions for extended periods may degrade
device reliability.

ABSOLUTE MAXIMUM RATINGS

(1)

Top View SO-8

PACKAGE SPECIFIED
DRAWING TEMPERATURE PACKAGE ORDERING TRANSPORT

PRODUCT PACKAGE NUMBER(1) RANGE MARKING NUMBER(2) MEDIA

INA146UA SO-8 182 –40°C to +85°C INA146UA INA146UA Rails

" " " " " INA146UA/2K5 Tape and Reel

NOTES: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book, or visit the Burr-Brown web site
at www.burr-brown.com. (2) Models with a slash (/ ) are available only in Tape and Reel in the quantities indicated (e.g., /2K5 indicates 2500 devices per reel).
Ordering 2500 pieces of “INA146UA/2K5” will get a single 2500-piece Tape and Reel. For detailed Tape and Reel mechanical information, refer to Appendix B of
Burr-Brown IC Data Book.

PACKAGE/ORDERING INFORMATION

INA146UA
PARAMETER CONDITION MIN TYP MAX UNITS
OFFSET VOLTAGE, V

O

RTI

(1, 2)

Input Offset Voltage V

OS

VS = ±15V, V

CM

= VO = 0V ±0.5 mV

vs Temperature ∆V

OS

/∆TT

A

= –40°C to +85°C ±1 µV/°C

INPUT VOLTAGE RANGE

Common-Mode Voltage Range V

CM

VIN+ – VIN– = 0V, VO = 0V (V–) to (V+) –1 V

Common-Mode Rejection Ratio CMRR V

CM

= (V–) to (V+) –1 90 dB

OPEN-LOOP GAIN

Open Loop Gain A

OL

110 dB

INPUT BIAS CURRENT

(2)

Bias Current I

B

±50 nA

Offset Current I

OS

±5nA

RESISTOR AT A1 OUTPUT, V

O1

Initial 10 kΩ
Error ±1%
Temperature Drift Coefficient ±100 ppm/°C

Ref

V

IN

V

IN

V–

–

+

V

O1

V+
V

O

R

G

1
2
3
4

8
7
6
5

5

®

INA146

TYPICAL PERFORMANCE CURVES

At TA = +25°C, VS = ±15V, G = 0.1, RL = 10kΩ connected to ground and Ref pin connected to ground, unless otherwise noted.

0.1Hz to 10Hz VOLTAGE NOISE (RTI)

500ms/div

2µV/div

GAIN vs FREQUENCY

Frequency (Hz)

Voltage Gain (dB)

100 1K 10K 1M 10M

40

20

0

–20

–40

100K

VS = ±15V

C

L

= 1000pF

G = 10

G = 1

G = 0.1

GAIN vs FREQUENCY

Frequency (Hz)

Voltage Gain (dB)

100 1K 10K 1M 10M

40

20

0

–20

–40

100K

VS = ±15V

C

L

= 200pF 10kΩ

G = 10

G = 0.1

G = 1

COMMON-MODE REJECTION vs FREQUENCY

Frequency (Hz)

Common-Mode Rejection (dB)

10 100 1k 1M 10M

100

80

60

40

20

0

10k 100k

POWER SUPPLY REJECTION vs FREQUENCY

Frequency (Hz)

Power Supply Rejection (dB)

1 10 100 10k 100k

100

80

60

40

20

0

1k

PSR+

(V

S

= ±15V)

PSR–

(V

S

= ±15V)

PSR+

(V

S

= +5V)

INPUT VOLTAGE NOISE DENSITY

Frequency (Hz)

Input Voltage Noise (nV/√Hz

0.1 1 10 10k 100k

10k

1k

100

100 1k

G = 0.1

G = 1

G = 10

6

®

INA146

TYPICAL PERFORMANCE CURVES (Cont.)

At TA = +25°C, VS = ±15V, G = 0.1, RL = 10kΩ connected to ground and Ref pin connected to ground, unless otherwise noted.

QUIESCENT CURRENT AND

SHORT-CIRCUIT CURRENT vs TEMPERATURE

Temperature (°C)

I

Q

(µA)

–60 –40 0–20 80 100

I

SC

I

Q

120

140

670
650
630
610
590
570
550
530
510
490
470

I

SC

(mA)

20
18
16
14
12
10
8
6
4
2
0

20

6040

G = 1

SLEW RATE vs TEMPERATURE

Temperature (°C)

Sew Rate (V/µs)

–60 –40 0–20 80 100

120

140

0.6

0.55

0.5

0.45

0.4

0.35

0.3

0.25

0.2
20

6040

G = 1

GAIN AND PHASE vs FREQUENCY

Op Amp A1 and A2

Frequency (Hz)

Open-Loop Gain (dB)

Phase (°)

1 10 100 100k 1M

110
100

90
80
70
60
50
40
30
20
10

0

–10

–90

–135

–180

1k 10k

RL = 10kΩ || 200pF

RL = 10kΩ || 1nF

Φ

G

SETTLING TIME vs LOAD CAPACITANCE

Load Capacitance (nF)

Settling Time (µs)

1 3 30 100

120

100

80

60

40

20

0

10

0.01%, G = 1

TS vs C

LOAD

VS = ±15V

0.1%, G = 0.1

0.1%, G = 1

+25°C

MAXIMUM OUTPUT VOLTAGE SWING

vs OUTPUT CURRENT

15

10

5

0

–5

–10

–15

0246810121416

Output Current (mA)

Output Voltage Swing (V)

+85°C

–25°C

+25°C

+85°C

+125°C

+85°C

–55°C

+125°C

–25°C

OFFSET VOLTAGE

PRODUCTION DISTRIBUTION

Percent of Amplifiers (%)

Offset Voltage, RTI (mV)

< –10

< –9

< –8

< –7

< –6

< –5

< –4

< –3

< –2

< –1

< 0

< 1

< 2

< 3

< 4

< 5

< 6

< 7

< 8

< 9

< 10

> 10

25

20

15

10

5

0

Typical production
distribution of
packaged units.

V

S

= ±2.25V

7

®

INA146

TYPICAL PERFORMANCE CURVES (Cont.)

At TA = +25°C, VS = ±15V, G = 0.1, RL = 10kΩ connected to ground and Ref pin connected to ground, unless otherwise noted.

SMALL-SIGNAL STEP RESPONSE

(G = 0.1, R

L

= 10kΩ, CL = 200pF)

5µs/div

50mV/div

SMALL-SIGNAL STEP RESPONSE

(G = 0.1, C

L

= 1000pF)

5µs/div

50mV/div

SMALL-SIGNAL STEP RESPONSE

(G = 1, C

L

= 1000pF)

5µs/div

50mV/div

LARGE-SIGNAL STEP RESPONSE

(G = 1, R

L

= 10kΩ, CL = 200pF)

50µs/div

5V/div

OFFSET VOLTAGE

PRODUCTION DISTRIBUTION

Percent of Amplifiers (%)

Offset Voltage, RTI (mV)

< –10

< –9

< –8

< –7

< –6

< –5

< –4

< –3

< –2

< –1

< 0

< 1

< 2

< 3

< 4

< 5

< 6

< 7

< 8

< 9

< 10

> 10

40
35
30
25
20
15
10

5
0

Typical production
distribution of
packaged units.

V

S

= ±15V

OFFSET VOLTAGE DRIFT

PRODUCTION DISTRIBUTION

Percent of Amplifiers (%)

Offset Voltage Drift, RTI (µV/°C)

–100

–90

–80

–70

–60

–50

–40

–30

–20

–10

0

102030405060708090

100

30

25

20

15

10

5

0

Typical production
distribution of
packaged units.

V

S

= ±15V

8

®

INA146

APPLICATION INFORMATION

The INA146 is a programmable gain difference amplifier
consisting of a gain of 0.1 difference amplifier and a pro­grammable-gain output buffer stage. Basic circuit connec­tions are shown in Figure 1. Power supply bypass capacitors
should be connected close to pins 4 and 7 as shown. The
amplifier is programmable in the range of G = 0.1 to G = 50
with two external resistors.

The output of A1 is connected to the noninverting input of
A2 through a 10kΩ resistor which is trimmed to ±1%
absolute accuracy. The A2 input is available for applications
such as a filter or a precision current source. See application
figures for examples.

OPERATING VOLTAGE

The INA146 is fully specified for supply voltages from
±2.25V to ±18V with key parameters guaranteed over the
temperature range –40°C to +85°C. The INA146 can be
operated with single or dual supplies with excellent perfor­mance. Parameters that vary significantly with operating
voltage, load conditions or temperature are shown in the
typical performance curves.

SETTING THE GAIN

The gain of the INA146 is set by using two external
resistors, RG1 and RG2, according to the equation:

G = 0.1 • (1 + RG2/RG1)

For a total gain of 0.1, A2 is connected as a buffer amplifier
with no RG1. A feedback resistor, RG2 = 10kΩ, should be
used in the buffer connection. This provides bias current
cancellation (in combination with internal R5) to assure
specified offset voltage performance. Commonly used val­ues are shown in the table of Figure 1. Resistor values for
other gains should be chosen to provide a 10kΩ parallel
resistance.

COMMON-MODE RANGE

The 10:1 input resistor ratio of the INA146 provides an input
common-mode range that can extend well beyond the power
supply rails. Exact range depends on the power supply
voltage and the voltage applied to the Ref terminal (pin 1).
To assure proper operation, the voltage at the non-inverting
input of A1 (an internal node) must be within its linear
operating range. Its voltage is determined by the simple 10:1
voltage divider between pin 3 and pin 1. This voltage must
be between V– and (V+) – 1V.

FIGURE 1. Basic Circuit Connections.

R

5

10kΩ

A1

V

IN

INA146

V

O

R

2

10kΩ

R

1

100kΩ

V

IN

R

3

100kΩ

R

4

10kΩ

R

G1

R

G2

R

B

A2

V

01

7

3

2

5

418

6

–V

S

+V

S

0.1µF

–

+

VO = (VIN – VIN) 0.1 (1 + RG2/RG1)

+–

TOTAL GAIN

A2 GAIN

R

G1

R

G2

R

B

(V/V) (V/V) (Ω)(Ω)(Ω)

0.1 1 (None) 10k —

0.2 2 20k 20k —

0.5 5 12.4k 49.9k —
1 10 11.0k 100k —
2 20 10.5k 200k —
5 50 10.2k 499k —

10 100 10.2k 1M —
20 200 499 100k 9.53k
50 500 100 49.9k 10k

100 1000 100 100k 10k

STANDARD 1% RESISTORS

0.1µF

9

®

INA146

FIGURE 2. Optional Offset Trim Circuit.

VIN+

V

O

1

A1

VIN–

100Ω

10kΩ

Offset Adjustment Range = ±15mV, RTI

(±1.5mV at pin 1)

R

T

100kΩ

10Ω

100kΩ

+15V

V

O1

–15V

R

3

R

1

R

2

R

5

A2

R

4

5

6

NOTE: Increasing the trim resistor
R

T

will decrease the trim range

VO = 1.08V nominal

Output scaled to low
voltage A/D converter.

+5V 40V

+7V 60V
+10V 95V
≥ 11V 100V

V+

+5V

14

8

Load

R

G2

10kΩ

10kΩ

INA146

5

7

6

2

Differential measurement at
battery rejects voltage drop
in connection resistance, R

X

.

3

V

IN

R

X

R

X

10.8V

+

V+ Max V

IN

FIGURE 3. Measuring Voltages Greater than Supply Voltage.

OFFSET TRIM

The INA146 is laser-trimmed for low offset voltage and
drift. Most applications require no external offset adjust­ment. Figure 2 shows an optional circuit for trimming the
offset voltage. A voltage applied to the Ref terminal will
be summed with the output signal. This can be used to null
offset voltage. To maintain good common-mode rejection,
the source impedance of a signal applied to the Ref
terminal should be less than 10Ω and a resistor added to
the positive input terminal should be 10 times that, or
100Ω. Alternatively, the trim voltage can be buffered with
an op amp such as the OPA277.

INPUT IMPEDANCE

The input impedance of the INA146 is determined by the
input resistor network and is approximately 100kΩ. The
source impedance at the two input terminals must be nearly
equal to maintain good common-mode rejection. A 12Ω
mismatch in impedance between the two inputs will cause
the typical common-mode rejection to be degraded to ap­proximately 72dB. Figure 7 shows a common application
measuring power supply current through a shunt resistor.
The source impedance of the shunt resistor, RS, is balanced
by an equal compensation resistor, RC.

Source impedances greater than 800Ω are not recommended,
even if they are perfectly matched. Internal resistors are laser
trimmed for accurate ratios, not to absolute values. Adding
equal resistors greater than 800Ω can cause a mismatch in
the total resistor ratios, degrading CMR.

10

®

INA146

FIGURE 4. Noise Filtering.

FIGURE 5. Output Clamp.

FIGURE 6. Precision Clamp.

V

O

18

6

V

IN

G = 1

Pole at

106Hz

R

G1

10kΩ

10kΩ

R

G2

1MΩ

22nF

INA146

5

2

3

1500pF

Pole at

720Hz

–

V

IN

+

V

O

18

6

R

G2

10kΩ

10kΩ

Output clamps at

approximately ±4V.

1N914

1N4684 (3.3V)

INA146

5

2

3

V

IN

–

V

IN

+

V

O

1

8

6

R

G2

10kΩ

R

1

R

2

R

3

R

4

10kΩ

5.0V
or analog-to-digital V

S

0V ≤ VO ≤ 5V

NOTE: (1) 1/2 OPA2342 with V

S

connected to +5V and GND.

Voltage

Reference

1N914

INA146

5

2

3

V

IN

–

V

IN

+

(1)

1N914

(1)

11

®

INA146

FIGURE 7. Current Monitor, G = 1.

FIGURE 8. Comparator Output with Optional Hysteresis Application to Sense Lamp Burn-Out.

FIGURE 9. AC Coupling (DC Restoration). FIGURE 10. Precision Current Source.

V

O

1V – 50mV

+5V

1

Ref

48

6

8.4kΩ

INA146

57

Feedback

2

3

10MΩ

8kΩ

10kΩ

1V

2kΩ

Lamp

24V

SHUNT

R-I Lamp/10

e.g., 0.1Ω for 1A

V

O

V

O1

18

6

R

G1

11kΩ

R

C

100Ω

R

S

100Ω

R

G2

100kΩ

INA146

5

2

Power

Supply

Load

3

For sense resistors (RS)
greater than 10Ω, use
series compensation
resistor (R

C

) for good
common-mode rejection.
Sense resistors greater
than 500Ω are not
recommended.

V

O

1

R

G1

11kΩ

R

G2

100kΩ

R

1

1MΩ

INA146

OPA277

5

2

3

C

1

0.1µF

V

IN

–

V

IN

+

Pole at

f = = 1.6Hz

1

2πR

1RC

V

O

I

OUT

– (VIN – VIN)/10kΩ

V

O1

18

6

R

G2

10kΩ

10kΩ

INA146

5

2

3

V

IN

–+

V

IN

+