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LT1168
1168fa
Low Power, Single
Resistor Gain Programmable,
Precision Instrumentation Amplifier
The LT
®
1168 is a micropower, precision instrumentation am-
plifier that requires only one external resistor to set gains of
1 to 10,000. The low voltage noise of 10nV/√Hz (at 1kHz) is
not compromised by low power dissipation (350µA typical for
±15V supplies). The wide supply range of ±2.3V to ±18V allows
the LT1168 to fit into a wide variety of industrial as well as
battery-powered applications.
The high accuracy of the LT1168 is due to a 20ppm maximum
nonlinearity and 0.4% max gain error (G = 10). Previous mono-
lithic instrumentation amps cannot handle a 2k load resistor
whereas the nonlinearity of the LT1168 is specified for loads
as low as 2k. The LT1168 is laser trimmed for very low input
offset voltage (40µV max), drift (0.3µV/°C), high CMRR (90dB,
G = 1) and PSRR (103dB, G = 1). Low input bias currents of
250pA max are achieved with the use of superbeta process-
ing. The output can handle capacitive loads up to 1000pF in
any gain configuration while the inputs are ESD protected up
to 13kV (human body). The LT1168 with two external 5k
resistors passes the IEC 1000-4-2 level 4 specification.
The LT1168 is a pin-for-pin improved second source for the
AD620 and INA118. The LT1168, offered in 8-pin PDIP and
SO packages, requires significantly less PC board area than
discrete op amp resistor designs. These advantages make
the LT1168 the most cost effective solution for precision
instrumentation amplifier applications.
■
Supply Current: 530µA Max
■
Meets IEC 1000-4-2 Level 4 (±15kV) ESD Tests
with Two External 5k Resistors
■
Single Gain Set Resistor: G = 1 to 10,000
■
Gain Error: G = 10, 0.4% Max
■
Input Offset Voltage Drift: 0.3µV/°C Max
■
Gain Nonlinearity: G = 10, 20ppm Max
■
Input Offset Voltage: 40µV Max
■
Input Bias Current: 250pA Max
■
PSRR at A
V
=1: 103dB Min
■
CMRR at A
V
= 1: 90dB Min
■
Wide Supply Range: ±2.3V to ±18V
■
1kHz Voltage Noise: 10nV/√Hz
■
0.1Hz to 10Hz Noise: 0.28µV
P-P
■
Available in 8-Pin PDIP and SO Packages
■
Bridge Amplifiers
■
Strain Gauge Amplifiers
■
Thermocouple Amplifiers
■
Differential to Single-Ended Converters
■
Differential Voltage to Current Converters
■
Data Acquisition
■
Battery-Powered and Portable Equipment
■
Medical Instrumentation
■
Scales
Single Supply* Pressure Monitor
NONLINEARITY (100ppm/DIV)
G = 1000 OUTPUT VOLTAGE (2V/DIV)
1168 TA01a
R
L
= 2k
V
OUT
= ± 10V
Gain Nonlinearity
*See Theory of Operation section
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U
–
+
2
3
2
1
1
1
1/2
LT1112
3.5k
5V
3.5k
3.5k
3.5k
8
7
6
1168 TA01
5
40k
20k
40k
DIGITAL
DATA
OUTPUT
4
R1
G = 200
249Ω
3
REF
IN
AGND
ADC
LTC
®
1286
BI TECHNOLOGIES
67-8-3 R40KQ, (0.02% RATIO MATCH)
–
+
LT1168
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
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