INA121

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FET-Input, Low Power Instrumentation Amplifier

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Product details

Parameters

Number of channels (#) 1 Vs (Max) (V) 36 Vs (Min) (V) 4.5 Input offset (+/-) (Max) (uV) 500 Gain (Min) (V/V) 1 Gain (Max) (V/V) 10000 Noise at 1 kHz (Typ) (nV/rt (Hz)) 20 Features Overvoltage Protection CMRR (Min) (dB) 106 Input offset drift (+/-) (Max) (uV/C) 5 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 Type Resistor Noise at 0.1 Hz-10 Hz (Typ) (uVpp) 1 Gain non-linearity (+/-) (Max) (%) 0.005 open-in-new Find other Instrumentation amplifiers

Package | Pins | Size

PDIP (P) 8 93 mm² 9.81 x 9.43 SOIC (D) 8 19 mm² 3.91 x 4.9 open-in-new Find other Instrumentation amplifiers

Features

  • 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

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Description

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 Sep. 27, 2000
Technical article What is an instrumentation amplifier? Aug. 09, 2019
E-book The Signal e-book: A compendium of blog posts on op amp design topics Mar. 28, 2017
Technical article How to layout a PCB for an instrumentation amplifier Oct. 14, 2016
User guide Universal Instrumentation Amplifier EVM User’s Guide (Rev. B) Aug. 09, 2016
Technical article Dealing with rejection: Instrumentation amplifier PSRR and CMRR (Part I) Nov. 25, 2013

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Hardware development

EVALUATION BOARD Download
document-generic User guide
Description

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 (...)

Design tools & simulation

SIMULATION MODEL Download
SBOC140B.TSC (91 KB) - TINA-TI Reference Design
SIMULATION MODEL Download
SBOM018A.ZIP (39 KB) - PSpice Model
SIMULATION TOOL Download
PSpice® for TI design and simulation tool
PSPICE-FOR-TI — 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 (...)
Features
  • Leverages Cadence PSpice Technology
  • Preinstalled library with a suite of digital models to enable worst-case timing analysis
  • Dynamic updates ensure you have access to most current device models
  • Optimized for simulation speed without loss of accuracy
  • Supports simultaneous analysis of multiple products
  • (...)
SIMULATION TOOL Download
SPICE-based analog simulation program
TINA-TI 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 (...)
document-generic User guide
CALCULATION TOOL Download
Analog engineer's calculator
ANALOG-ENGINEER-CALC — 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 op-amp gain with feedback (...)
Features
  • Expedites circuit design with analog-to-digital converters (ADCs) and digital-to-analog converters (DACs)
    • Noise calculations
    • Common unit translation
  • Solves common amplifier circuit design problems
    • Gain selections using standard resistors
    • Filter configurations
    • Total noise for common amplifier configurations
  • (...)

CAD/CAE symbols

Package Pins Download
PDIP (P) 8 View options
SOIC (D) 8 View options

Ordering & quality

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  • Ongoing reliability monitoring

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