LT1168
Low Power, Single
Resistor Gain Programmable,
Precision Instrumentation Amplifier
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FEATURES
DESCRIPTIO
TheLT®1168isamicropower,precisioninstrumentationam-
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Supply Current: 530µA Max
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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 AV =1: 103dB Min
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
notcompromisedbylowpowerdissipation(350µAtypicalfor
±15Vsupplies).Thewidesupplyrangeof±2.3Vto±18Vallows
the LT1168 to fit into a wide variety of industrial as well as
battery-powered applications.
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ThehighaccuracyoftheLT1168isduetoa20ppmmaximum
nonlinearityand0.4%maxgainerror(G=10).Previousmono-
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
offsetvoltage(40µVmax),drift(0.3µV/°C),highCMRR(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.
CMRR at AV = 1: 90dB Min
Wide Supply Range: ±2.3V to ±18V
1kHz Voltage Noise: 10nV/√Hz
0.1Hz to 10Hz Noise: 0.28µVP-P
Available in 8-Pin PDIP and SO Packages
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APPLICATIO S
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Bridge Amplifiers
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Strain Gauge Amplifiers
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TheLT1168isapin-for-pinimprovedsecondsourceforthe
AD620andINA118.TheLT1168,offeredin8-pinPDIPand
SOpackages,requiressignificantlylessPCboardareathan
discrete op amp resistor designs. These advantages make
the LT1168 the most cost effective solution for precision
instrumentation amplifier applications.
Thermocouple Amplifiers
Differential to Single-Ended Converters
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Differential Voltage to Current Converters
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Data Acquisition
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Battery-Powered and Portable Equipment
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Medical Instrumentation
Scales
, 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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TYPICAL APPLICATIO
Single Supply* Pressure Monitor
Gain Nonlinearity
BI TECHNOLOGIES
67-8-3 R40KQ, (0.02% RATIO MATCH)
5V
1
3
8
40k
+
–
7
3.5k
3.5k
3.5k
3.5k
REF
IN
R1
G = 200
249Ω
6
LT1168
4
DIGITAL
ADC
20k
DATA
LTC®1286
1
2
5
OUTPUT
3
+
1
1/2
AGND
40k
LT1112
2
–
G = 1000
OUTPUT VOLTAGE (2V/DIV)
1168 TA01a
R
OUT
= 2k
L
1168 TA01
V
= ± 10V
*See Theory of Operation section
1168fa
1