LT1991 - Precision, 100µA Gain Selectable Amplifier

Features

  • Pin Configurable as a Difference Amplifier, Inverting and Noninverting Amplifier
  • Difference Amplifier
    Gain Range 1 to 13
    CMRR >75dB
  • Noninverting Amplifier
    Gain Range 0.07 to 14
  • Inverting Amplifier
    Gain Range -0.08 to -13
  • Gain Error <0.04%
  • Gain Drift < 3ppm/°C
  • Wide Supply Range: Single 2.7V to Split ±18V
  • Micropower: 100µA Supply Current
  • Precision: 50µV Maximum Input Offset Voltage
  • 560kHz Gain Bandwidth Product
  • Rail-to-Rail Output
  • Space Saving 10-Lead MSOP and DFN Packages

Typical Application

LT1991 Typical Application
LT1991 Typical Application

Description

The LT1991 combines a precision operational amplifier with eight precision resistors to form a one-chip solution for accurately amplifying voltages. Gains from -13 to 14 with a gain accuracy of 0.04% can be achieved using no external components. The device is particularly well suited for use as a difference amplifier, where the excellent resistor matching results in a common mode rejection ratio of greater than 75dB.

The amplifier features a 50µV maximum input offset voltage and a gain bandwidth product of 560kHz. The device operates from any supply voltage from 2.7V to 36V and draws only 100µA supply current on a 5V supply. The output swings to within 40mV of either supply rail.

The resistors have excellent matching, 0.04% over temperature for the 450k resistors. The matching temperature coefficent is guaranteed less than 3ppm/°C. The resistors are extremely linear with voltage, resulting in a gain nonlinearity of less than 10ppm.

The LT1991 is fully specified at 5V and ±15V supplies and from -40°C to 85°C. The device is available in space saving 10-lead MSOP and low profile (0.8mm) 3mm × 3mm DFN packages.

 

Packaging

For complete and up to date package information and drawings, please refer to our packaging page

MS-10, DFN-10

LT1991 Package Drawing
LT1991 Package Drawing

Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LT1991ACDD DFN 10 C $2.52 $2.09 View
LT1991ACDD#PBF DFN 10 C $2.52 $2.09 View
LT1991ACDD#TR DFN 10 C $2.15 View
LT1991ACDD#TRPBF DFN 10 C $2.15 View
LT1991ACMS MSOP 10 C $2.28 $1.89 View
LT1991ACMS#PBF MSOP 10 C $2.28 $1.89 View
LT1991ACMS#TR MSOP 10 C $1.95 View
LT1991ACMS#TRPBF MSOP 10 C $1.95 View
LT1991AIDD DFN 10 I $3.01 $2.49 View
LT1991AIDD#PBF DFN 10 I $3.01 $2.49 View
LT1991AIDD#TR DFN 10 I $2.55 View
LT1991AIDD#TRPBF DFN 10 I $2.55 View
LT1991AIMS MSOP 10 I $2.77 $2.29 View
LT1991AIMS#PBF MSOP 10 I $2.77 $2.29 View
LT1991AIMS#TR MSOP 10 I $2.35 View
LT1991AIMS#TRPBF MSOP 10 I $2.35 View
LT1991CDD DFN 10 C $2.10 $1.59 View
LT1991CDD#PBF DFN 10 C $2.10 $1.59 View
LT1991CDD#TR DFN 10 C $1.65 View
LT1991CDD#TRPBF DFN 10 C $1.65 View
LT1991CMS MSOP 10 C $1.80 $1.39 View
LT1991CMS#PBF MSOP 10 C $1.80 $1.39 View
LT1991CMS#TR MSOP 10 C $1.45 View
LT1991CMS#TRPBF MSOP 10 C $1.45 View
LT1991HDD DFN 10 H $2.30 $1.90 View
LT1991HDD#PBF DFN 10 H $2.30 $1.90 View
LT1991HDD#TR DFN 10 H $1.96 View
LT1991HDD#TRPBF DFN 10 H $1.96 View
LT1991HMS MSOP 10 H $2.05 $1.69 View
LT1991HMS#PBF MSOP 10 H $2.05 $1.69 View
LT1991HMS#TR MSOP 10 H $1.75 View
LT1991HMS#TRPBF MSOP 10 H $1.75 View
LT1991IDD DFN 10 I $2.30 $1.90 View
LT1991IDD#PBF DFN 10 I $2.30 $1.90 View
LT1991IDD#TR DFN 10 I $1.96 View
LT1991IDD#TRPBF DFN 10 I $1.96 View
LT1991IMS MSOP 10 I $2.05 $1.69 View
LT1991IMS#PBF MSOP 10 I $2.05 $1.69 View
LT1991IMS#TR MSOP 10 I $1.75 View
LT1991IMS#TRPBF MSOP 10 I $1.75 View
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC819A LT1990CS8/LT1991CMS/LT1995CMS | Configurable Gain Amplifiers, V+ = +2.5V to +15V, V- = -2.5V to -15V $75.00
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Applications

  • Handheld Instrumentation
  • Medical Instrumentation
  • Strain Gauge Amplifiers
  • Differential to Single-Ended Conversion

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Simulate

LTspice IV is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. To download LTspice IV and other FREE simulation tools, please visit our Design Simulation page.

Related models available in LTspice IV
LT1991

The 'Configurator' is a design tool that generates the complete schematic for an amplifier stage designed with one of Linear Technology's Gain Selectable Amplifiers, the LT1991, LT1995 or LT1996. Simply enter the type of input signal (single ended or differential), the available supply voltage and the gain. The 'Configurator' generates a schematic of the best pin configuration and indicates key performance characteristics.

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