A

1

A

2

A

3

40 kW

40 kW

40 kW

40 kW

V

IN

2

1

8

3

6

5

V

IN

R

G

V+

V-

Ref

V

O

G = 1 +

49.4 kW

R

G

+

4

7

INA129

Over-Voltage

Protection

Over-Voltage

Protection

24.7 kW

24.7 kW

-

INA129-EP

www.ti.com

SBOS508A – DECEMBER 2009 – REVISED DECEMBER 2015

7 Detailed Description

7.1 Overview

The INA129-EP instrumentation amplifier is a type of differential amplifier that has been outfitted with input

protection circuit and input buffer amplifiers, which eliminate the need for input impedance matching and make

the amplifier particularly suitable for use in measurement and test equipment. Additional characteristics of the

INA129-EP include a very low DC offset, low drift, low noise, very high open-loop gain, very high common-mode

rejection ratio, and very high input impedances. The INA129-EP is used where great accuracy and stability of the

circuit both short and long-term are required.

7.2 Functional Block Diagram

7.3 Feature Description

The INA129-EP device is a low power, general-purpose instrumentation amplifier that offers excellent accuracy.

The versatile three-operational-amplifier design and small size make the amplifier ideal for a wide range of

applications. Current-feedback input circuitry provides wide bandwidth, even at high gain. A single external

resistor sets any gain from 1 to 10,000. The INA129-EP device is laser trimmed for very low offset voltage (50

μV) and high common-mode rejection (93 dB at G ≥ 100). This device operates with power supplies as low as

±2.25 V, and quiescent current of 2 mA, typically. The internal input protection can withstand up to ±40 V without

damage.

Copyright © 2009–2015, Texas Instruments Incorporated

Submit Documentation Feedback

11

Product Folder Links: INA129-EP