INA12x Precision, Low-Power Instrumentation Amplifiers

1 Features

• Low offset voltage: 50 μV, maximum

• Low drift: 0.5 μV/°C, maximum

• Low input bias current: 5 nA, maximum

• Low noise: 8 nV/√Hz, 0.2 μVpp

• High CMR: 120 dB, minimum

• Bandwidth: 1.3 MHz (G = 1)

• Inputs protected to ±40 V

• Wide supply range: ±2.25 V to ±18 V

• Low quiescent current: 700 μA

• Packages: 8-pin plastic DIP, SO-8

2 Applications

• Pressure transmitter

• Temperature transmitter

• Weigh scale

• Electrocardiogram (ECG)

• Analog input module

• Data acquisition (DAQ)

3 Description

The INA128 and INA129 (INA12x) are low-power,

general-purpose instrumentation amplifiers that offer

excellent accuracy. The versatile three op amp design

and small size make these amplifiers an excellent

choice for a wide range of applications. Current-

feedback input circuitry provides wide bandwidth even

at high gain (200 kHz at G = 100).

A single external resistor sets any gain from 1 to

10,000. The INA128 provides an industry-standard

gain equation with a 50-kΩ resistor. The INA129 gain

equation uses a 49.4-kΩ resistor to allow for drop-in

replacements of comparable devices.

The INA12x are available in plastic DIP and surface-

mount packages, specified for the –40°C to +85°C

temperature range. The INA128 is also available in a

dual configuration, the INA2128.

The upgraded INA828 offers a lower input bias

current (0.6 nA, max) and lower noise (7 nV/√Hz)

at the same quiescent current. See the Device

Comparison Table for a selection of precision

instrumentation amplifiers from Texas Instruments.

Device Information

PART NUMBER

PACKAGE(1)

BODY SIZE (NOM)

INA128,

INA129

SOIC (8)

3.91 mm × 4.90 mm

PDIP (8)

6.35 mm × 9.81 mm

(1)

For all available packages, see the package option

addendum at the end of the data sheet.

A

1

A

2

A

3

6

7

4

3

8

1

2

RG

V+

INA128, INA129

5

Overvoltage

Protection

Protection

(1) INA129: 24.7 k

V

25 k

(1)

25 k

(1)

40 k

40 k

40 k

40 k

Overvoltage

VIN–

VIN+

VO

Ref

G = 1 +

49.4 k

R

G

G = 1 +

50 k

R

G

INA128:

INA129:

Simplified Schematic

INA128, INA129

SBOS051F – OCTOBER 1995 – REVISED MAY 2022

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.