FEATURES
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LT1168
Low Power, Single
Resistor Gain Programmable,
Precision Instrumentation Amplifier
DESCRIPTIO
The LT
廬
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/鈭欻z (at 1kHz) is
not compromised by low power dissipation (350碌A typical for
鹵15V
supplies). The wide supply range of
鹵2.3V
to
鹵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 (40碌V max), drift (0.3碌V/擄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.
, LTC and LT are registered trademarks of Linear Technology Corporation.
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Supply Current: 530碌A Max
Meets IEC 1000-4-2 Level 4 (鹵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: 0.3碌V/擄C Max
Gain Nonlinearity: G = 10, 20ppm Max
Input Offset Voltage: 40碌V Max
Input Bias Current: 250pA Max
PSRR at A
V
=1: 103dB Min
CMRR at A
V
= 1: 90dB Min
Wide Supply Range:
鹵2.3V
to
鹵18V
1kHz Voltage Noise: 10nV/鈭欻z
0.1Hz to 10Hz Noise: 0.28碌V
P-P
Available in 8-Pin PDIP and SO Packages
APPLICATIO S
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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
TYPICAL APPLICATIO
5V
Single Supply* Pressure Monitor
BI TECHNOLOGIES
67-8-3 R40KQ, (0.02% RATIO MATCH)
1
3.5k
3.5k
3
8
R1
G = 200
249鈩?/div>
1
2
+
40k
7
REF
LT1168
5
6
20k
3
40k
2
IN
ADC
LTC
廬
1286
1
AGND
DIGITAL
DATA
OUTPUT
3.5k
3.5k
鈥?/div>
+
1/2
LT1112
4
鈥?/div>
1168 TA01
NONLINEARITY (100ppm/DIV)
*See Theory of Operation section
U
U
U
Gain Nonlinearity
G = 1000
R
L
= 2k
V
OUT
=
鹵10V
OUTPUT VOLTAGE (2V/DIV)
1168 TA01a
1
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