LT1991 - Precision, 100µA Gain Selectable Amplifier

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.

  • 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
  • Handheld Instrumentation
  • Medical Instrumentation
  • Strain Gauge Amplifiers
  • Differential to Single-Ended Conversion
LT1991 Package Drawing
LT1991 Package Drawing
Order Information
Part NumberPackageTempPrice(1-99)Price (1k)*
LT1991ACDD#PBF3x3 DFN-10C$2.52$2.09
LT1991ACDD#TRPBF3x3 DFN-10C$2.15
LT1991AIDD#PBF3x3 DFN-10I$3.01$2.49
LT1991AIDD#TRPBF3x3 DFN-10I$2.55
LT1991CDD#PBF3x3 DFN-10C$2.10$1.59
LT1991CDD#TRPBF3x3 DFN-10C$1.65
LT1991HDD#PBF3x3 DFN-10H$2.30$1.90
LT1991HDD#TRPBF3x3 DFN-10H$1.96
LT1991IDD#PBF3x3 DFN-10I$2.30$1.90
LT1991IDD#TRPBF3x3 DFN-10I$1.96
Demo Boards
Part NumberDescriptionPrice
DC819ALT1990CS8/LT1991CMS/LT1995CMS | Configurable Gain Amplifiers, V+ = +2.5V to +15V, V- = -2.5V to -15V$75.00
Design Note
Reliability Data
LT Journal
Press Release
Software and Simulation
CAD Symbol
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LT1991 - Product Press Release
The Configurator Software Download
LT1991 Footprints and Symbols