LT1991 Datasheet, PDF (1/24 Pages) Linear Integrated Systems – Precision, 100UA 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}
U
APPLICATIO S
■ _{Handheld Instrumentation}
■ _{Medical Instrumentation}
■ _{Strain Gauge Amplifiers}
■ _{Differential to Single-Ended Conversion}
LT1991
Precision, 100µA
Gain Selectable Amplifier
DESCRIPTIO
The LT^®1991 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 tem-
perature 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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners. Patent Pending.
TYPICAL APPLICATIO
V_M(IN) ^–
∆V_IN
+
V_P(IN)
INPUT RANGE
–0.5V TO 5.1V
R_IN = 900kΩ
Rail-to-Rail Gain = 1 Difference Amplifier
5V
50k
150k
450k
450k
150k
50k
450k
–
4pF
+
LT1991
450k
4pF
V_OUT = V_REF + ∆V_IN
SWING 40mV TO
EITHER RAIL
R_OUT <0.1Ω
V_REF = 2.5V
1991 TA01
Distribution of Resistor Matching
40
450k RESISTORS
35 ^LT1991A
30
25
20
15
10
5
0
– 0.04
– 0.02
0
0.02
0.04
RESISTOR MATCHING (%)
1991TA01b
1991fb
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