LINEAR TECHNOLOGY LT1991 High Precision, Selectable Gain Amplifier Data Sheet Owner's Manual
Summary
The LT1991 is a highly precise, low-power gain-selectable differential amplifier designed for demanding applications like medical instrumentation and strain gauge measurement. Integrating eight precision resistors, it offers excellent common mode rejection (CMRR >75dB) and operates across a wide supply range (2.7V to 36V). This technical resource provides detailed specifications, typical circuit examples, thermal data, and package information, making it essential for engineers implementing high-accuracy signal conditioning in handheld or industrial devices.
Page 1 Text Content
LT1991
Precision, 100µA
Gain Selectable Amplifi er
FEATURES DESCRIPTION n Pin Confi gurable as a Difference Amplifi er,
The LT®1991 combines a precision operational amplifi er
Inverting and Noninverting Amplifi er with eight precision resistors to form a one-chip solution n Difference Amplifi er for accurately amplifying voltages. Gains from –13 to 14 Gain Range 1 to 13 with a gain accuracy of 0.04% can be achieved using no CMRR >75d B external components. The device is particularly well suited n Noninverting Amplifi er for use as a difference amplifi er, where the excellent resis-
Gain Range 0.07 to 14 tor matching results in a common mode rejection ratio of
n Inverting Amplifi er greater than 75d B. Gain Range –0.08 to –13
The amplifi er features a 50μV maximum input offset volt-
n Gain Error <0.04%
age and a gain bandwidth product of 560k Hz. The device
n Gain Drift < 3ppm/°C
operates from any supply voltage from 2.7V to 36V and
n Wide Supply Range: Single 2.7V to Split ±18V
draws only 100μA supply current on a 5V supply. The
n Micropower: 100μA Supply Current
output swings to within 40m V of either supply rail.
n Precision: 50μV Maximum Input Offset Voltage
n 560k Hz Gain Bandwidth Product The resistors have excellent matching, 0.04% over tem- n Rail-to-Rail Output perature for the 450k resistors. The matching temperature
TA IT
coeffi cent is guaranteed less than 3ppm/°C. The resistors
n Space Saving 10-Lead MSOP and DFN Packages
are extremely linear with voltage, resulting in a gain non- linearity of less than 10ppm.
APPLICATIONS
The LT1991 is fully specifi ed at 5V and ±15V supplies and
n Handheld Instrumentation
from –40°C to 125°C. The device is available in space
n Medical Instrumentation
saving 10-lead MSOP and low profi le (0.8mm) 3mm ×
n Strain Gauge Amplifi ers
3mm DFN packages.
n Differential to Single-Ended Conversion
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
Rail-to-Rail Gain = 1 Difference Amplifi er
VOUT = VREF ΔVIN Distribution of Resistor Matching
5V SWING 40m V TO
EITHER RAIL 450k RESISTORS ROUT <0.1Ω LT1991A
VM(IN)
VP(IN) LT1991
INPUT RANGE –0.5V TO 5.1V
RIN = 900kΩ 50k
VREF = 2.5V RESISTOR MATCHING (%)
1991 TA01
1991 TA01b
1991fg
Page Summary Contents For LINEAR TECHNOLOGY LT1991 High Precision, Selectable Gain Amplifier Data Sheet Owner's Manual
Manual Details
| Brand | Linear |
|---|---|
| Pages | 28 |
| File Size | 290.26 KB |
| Published | June 22, 2026 |
Enter the captcha to get the download link:
Frequently Asked Questions
What is the operational gain range of the LT1991 amplifier?
The device supports a wide gain range from –13 to 14.
How efficient is the LT1991 in terms of power consumption?
It features micropower operation, drawing only 100µA supply current on a 5V supply.
What temperature extremes can the LT1991 handle?
Operating ranges vary by model; the LT1991H version supports –40°C to 125°C operation and storage.
Is this device suitable for space-constrained designs?
Yes, it is available in small 10-Lead MSOP and DFN packages.