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
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific 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

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

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

Part Number Package Code Temp Package
Drawing
RoHS
LT1991ACDD#PBF 3x3 DFN-10 DD C 05-08-1699 Yes
LT1991ACDD#TRPBF 3x3 DFN-10 DD C 05-08-1699 Yes
LT1991ACMS#PBF MS-10 MS C 05-08-1661 Yes
LT1991ACMS#TRPBF MS-10 MS C 05-08-1661 Yes
LT1991AIDD#PBF 3x3 DFN-10 DD I 05-08-1699 Yes
LT1991AIDD#TRPBF 3x3 DFN-10 DD I 05-08-1699 Yes
LT1991AIMS#PBF MS-10 MS I 05-08-1661 Yes
LT1991AIMS#TRPBF MS-10 MS I 05-08-1661 Yes
LT1991CDD#PBF 3x3 DFN-10 DD C 05-08-1699 Yes
LT1991CDD#TRPBF 3x3 DFN-10 DD C 05-08-1699 Yes
LT1991CMS#PBF MS-10 MS C 05-08-1661 Yes
LT1991CMS#TRPBF MS-10 MS C 05-08-1661 Yes
LT1991HDD#PBF 3x3 DFN-10 DD H 05-08-1699 Yes
LT1991HDD#TRPBF 3x3 DFN-10 DD H 05-08-1699 Yes
LT1991HMS#PBF MS-10 MS H 05-08-1661 Yes
LT1991HMS#TRPBF MS-10 MS H 05-08-1661 Yes
LT1991IDD#PBF 3x3 DFN-10 DD I 05-08-1699 Yes
LT1991IDD#TRPBF 3x3 DFN-10 DD I 05-08-1699 Yes
LT1991IMS#PBF MS-10 MS I 05-08-1661 Yes
LT1991IMS#TRPBF MS-10 MS I 05-08-1661 Yes


LT1991 Package Drawing
LT1991 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LT1991ACDD#PBF 3x3 DFN-10 C $2.52 $2.09 Yes
LT1991ACDD#TRPBF 3x3 DFN-10 C $2.15 Yes
LT1991ACMS#PBF MS-10 C $2.28 $1.89 Yes
LT1991ACMS#TRPBF MS-10 C $1.95 Yes
LT1991AIDD#PBF 3x3 DFN-10 I $3.01 $2.49 Yes
LT1991AIDD#TRPBF 3x3 DFN-10 I $2.55 Yes
LT1991AIMS#PBF MS-10 I $2.77 $2.29 Yes
LT1991AIMS#TRPBF MS-10 I $2.35 Yes
LT1991CDD#PBF 3x3 DFN-10 C $2.10 $1.59 Yes
LT1991CDD#TRPBF 3x3 DFN-10 C $1.65 Yes
LT1991CMS#PBF MS-10 C $1.80 $1.39 Yes
LT1991CMS#TRPBF MS-10 C $1.45 Yes
LT1991HDD#PBF 3x3 DFN-10 H $2.30 $1.90 Yes
LT1991HDD#TRPBF 3x3 DFN-10 H $1.96 Yes
LT1991HMS#PBF MS-10 H $2.05 $1.69 Yes
LT1991HMS#TRPBF MS-10 H $1.75 Yes
LT1991IDD#PBF 3x3 DFN-10 I $2.30 $1.90 Yes
LT1991IDD#TRPBF 3x3 DFN-10 I $1.96 Yes
LT1991IMS#PBF MS-10 I $2.05 $1.69 Yes
LT1991IMS#TRPBF MS-10 I $1.75 Yes
Buy NowRequest Samples
* 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
Buy Now
Click here to view our complete list of demo boards

Designed for Automotive and Transportation Applications

AEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LT1991AIMS#PBF MS-10 I $2.77 $2.29 Yes
LT1991AIMS#TRPBF MS-10 I $2.35 Yes
LT1991HMS#PBF MS-10 H $2.05 $1.69 Yes
LT1991HMS#TRPBF MS-10 H $1.75 Yes
LT1991IMS#PBF MS-10 I $2.05 $1.69 Yes
LT1991IMS#TRPBF MS-10 I $1.75 Yes
Buy NowRequest Samples
* 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.

Applications

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

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Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

Models for the following parts are available in LTspice:
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.

Technical Support