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INA121

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FET-Input, Low Power Instrumentation Amplifier

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Data sheet

INA121

ACTIVE
Data sheet Order now

Product details

Number of channels 1 Vs (max) (V) 36 Vs (min) (V) 4.5 Input offset (±) (max) (µV) 500 Voltage gain (min) (V/V) 1 Voltage gain (max) (V/V) 10000 Noise at 1 kHz (typ) (nV√Hz) 20 Features Overvoltage protection CMRR (min) (dB) 106 Input offset drift (±) (max) (V/°C) 0.000005 Input bias current (±) (max) (nA) 0.05 Iq (typ) (mA) 0.45 Bandwidth at min gain (typ) (MHz) 0.6 Gain error (±) (max) (%) 0.5 Operating temperature range (°C) -40 to 85 Rating Catalog Type Resistor Gain nonlinearity (±) (max) (%) 0.005 Output swing headroom (to negative supply) (typ) (V) 0.15 Output swing headroom (to positive supply) (typ) (V) -0.9 Input common mode headroom (to negative supply) (typ) (V) 2 Input common mode headroom (to positive supply) (typ) (V) -2 Noise at 0.1 Hz to 10 Hz (typ) (µVPP) 1
Number of channels 1 Vs (max) (V) 36 Vs (min) (V) 4.5 Input offset (±) (max) (µV) 500 Voltage gain (min) (V/V) 1 Voltage gain (max) (V/V) 10000 Noise at 1 kHz (typ) (nV√Hz) 20 Features Overvoltage protection CMRR (min) (dB) 106 Input offset drift (±) (max) (V/°C) 0.000005 Input bias current (±) (max) (nA) 0.05 Iq (typ) (mA) 0.45 Bandwidth at min gain (typ) (MHz) 0.6 Gain error (±) (max) (%) 0.5 Operating temperature range (°C) -40 to 85 Rating Catalog Type Resistor Gain nonlinearity (±) (max) (%) 0.005 Output swing headroom (to negative supply) (typ) (V) 0.15 Output swing headroom (to positive supply) (typ) (V) -0.9 Input common mode headroom (to negative supply) (typ) (V) 2 Input common mode headroom (to positive supply) (typ) (V) -2 Noise at 0.1 Hz to 10 Hz (typ) (µVPP) 1
PDIP (P) 8 92.5083 mm² 9.81 x 9.43 SOIC (D) 8 29.4 mm² 4.9 x 6
  • LOW BIAS CURRENT: ±4pA
  • LOW QUIESCENT CURRENT: ±450µA
  • LOW INPUT OFFSET VOLTAGE: ±200µV
  • LOW INPUT OFFSET DRIFT: ±2µV/°C
  • LOW INPUT NOISE: 20nV/sqrt(Hz) at f = 1kHz (G =100)
  • HIGH CMR: 106dB
  • WIDE SUPPLY RANGE: ±2.25V to ±18V
  • LOW NONLINEARITY ERROR: 0.001% max
  • INPUT PROTECTION TO ±40V
  • 8-PIN DIP AND SO-8 SURFACE MOUNT
  • LOW BIAS CURRENT: ±4pA
  • LOW QUIESCENT CURRENT: ±450µA
  • LOW INPUT OFFSET VOLTAGE: ±200µV
  • LOW INPUT OFFSET DRIFT: ±2µV/°C
  • LOW INPUT NOISE: 20nV/sqrt(Hz) at f = 1kHz (G =100)
  • HIGH CMR: 106dB
  • WIDE SUPPLY RANGE: ±2.25V to ±18V
  • LOW NONLINEARITY ERROR: 0.001% max
  • INPUT PROTECTION TO ±40V
  • 8-PIN DIP AND SO-8 SURFACE MOUNT

The INA121 is a FET-input, low power instrumentation amplifier offering excellent accuracy. Its versatile three-op amp design and very small size make it ideal for a variety of general purpose applications. Low bias current (±4pA) allows use with high impedance sources.

Gain can be set from 1V to 10,000V/V with a single external resistor. Internal input protection can withstand up to ±40V without damage.

The INA121 is laser-trimmed for very low offset voltage (±200µV), low offset drift (±2µV/°C), and high common-mode rejection (106dB at G = 100). It operates on power supplies as low as ±2.25V (+4.5V), allowing use in battery operated and single 5V systems. Quiescent current is only 450µA.

Package options include 8-pin plastic DIP and SO-8 surface mount. All are specified for the -40°C to +85°C industrial temperature range.

The INA121 is a FET-input, low power instrumentation amplifier offering excellent accuracy. Its versatile three-op amp design and very small size make it ideal for a variety of general purpose applications. Low bias current (±4pA) allows use with high impedance sources.

Gain can be set from 1V to 10,000V/V with a single external resistor. Internal input protection can withstand up to ±40V without damage.

The INA121 is laser-trimmed for very low offset voltage (±200µV), low offset drift (±2µV/°C), and high common-mode rejection (106dB at G = 100). It operates on power supplies as low as ±2.25V (+4.5V), allowing use in battery operated and single 5V systems. Quiescent current is only 450µA.

Package options include 8-pin plastic DIP and SO-8 surface mount. All are specified for the -40°C to +85°C industrial temperature range.
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Technical documentation

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Type Title Date
* Data sheet FET-Input, Low Power Instrumentation Amplifier datasheet 27 Sep 2000
Application note Importance of Input Bias Current Return Paths in Instrumentation Amplifier Apps PDF | HTML 27 Jul 2021
Technical article What is an instrumentation amplifier? 09 Aug 2019
E-book The Signal e-book: A compendium of blog posts on op amp design topics 28 Mar 2017
Technical article How to layout a PCB for an instrumentation amplifier 14 Oct 2016
EVM User's guide Universal Instrumentation Amplifier EVM User’s Guide (Rev. B) PDF | HTML 09 Aug 2016
Technical article Dealing with rejection: Instrumentation amplifier PSRR and CMRR (Part I) 25 Nov 2013

Design & development

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Evaluation board

INAEVM — Universal Instrumentation Amplifier Evaluation Module

The universal INAEVM (Instrumentation Amplifier Evaluation Module) is available in two package options that simplify prototyping precision instrumentation amplifiers in either the SO-8 (D) package or the MSOP-8(DGK) package with the pinout shown.  See the chart in the user guide (...)

User guide: PDF | HTML
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Simulation model

INA121 PSpice Model (Rev. B)

SBOM018B.ZIP (25 KB) - PSpice Model
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Simulation model

INA121 TINA-TI Reference Design (Rev. B)

SBOC140B.TSC (91 KB) - TINA-TI Reference Design
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Calculation tool

ANALOG-ENGINEER-CALC — Analog engineer's calculator

The analog engineer’s calculator is designed to speed up many of the repetitive calculations that analog circuit design engineers use on a regular basis. This PC-based tool provides a graphical interface with a list of various common calculations ranging from setting operational-amplifier (...)
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Simulation tool

PSPICE-FOR-TI — PSpice® for TI design and simulation tool

PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
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Simulation tool

TINA-TI — SPICE-based analog simulation program

TINA-TI provides all the conventional DC, transient and frequency domain analysis of SPICE and much more. TINA has extensive post-processing capability that allows you to format results the way you want them. Virtual instruments allow you to select input waveforms and probe circuit nodes voltages (...)
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PDIP (P) 8 View options
SOIC (D) 8 View options
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