LMP7312 Datasheet, PDF (1/22 Pages) National Semiconductor (TI) – Precision SPI-Programmable AFE with Differential/Single-Ended Input/Output

LMP7312
June 18, 2010
Precision SPI-Programmable AFE with Differential/Single-
Ended Input/Output
General Description
The LMP7312 is a digitally programmable variable gain am-
plifier/attenuator. Its wide input voltage range and superior
precision make it a prime choice for applications requiring
high accuracy such as data acquisition systems for IO mod-
ules in programmable logic control (PLC). The LMP7312
provides a differential output to maximize dynamic range and
signal to noise ratio, thereby reducing the overall system er-
ror. It can also be configured to handle single ended input data
converters by means of the V_OCM pin (see application section
for details). The inputs of LMP7312 can be configured in at-
tenuation mode to handle large input signals of up to +/- 15V,
as well as in amplification mode to handle current loops of
0-20mA and 4-20mA.The LMP7312 is equipped with a null
switch to evaluate the offset of the internal amplifier. A guar-
anteed 0.035% maximum gain error (for all gains) and a
maximum gain drift of 5ppm over the extended industrial tem-
perature range (-40° to 125°C) make the LMP7312 very
attractive for high precision systems even under harsh con-
ditions. A low input offset voltage of 100µV and low voltage
noise of 3µVpp give the LMP7312 a superior performance.
The LMP7312 is fully specified from -40° to 125°C and is
available in SOIC-14 package.
Features
Typical Values, T_A = 25°C, V⁺=5V, V^-=0V.
■ ^{Gain bandwidth}
1 MHz
■ ^{Input voltage range (G= 0.096 V/V)}
-15V to +15V
■ ^{Core op-amp input offset voltage}
100 µV (max)
■ ^{Supply current}
2 mA (max)
■ ^{Gain (Attenuation Mode)}
0.096 V/V, 0.192 V/V
0.384 V/V, 0.768 V/V
■ ^{Gain (AmplificationMode)}
1 V/V, 2 V/V
■ ^{Gain Error}
0.035% (max)
■ ^{Core op-amp PSRR}
90 dB (min)
■ ^CMRR
80 dB (min)
■ ^{Adjustable output common mode}
1V to 4V
■ ^{Temperature range}
−40 to 125°C
■ ^Package
14-Pin SOIC
Applications
■ ^{Signal conditioning AFE}
±10V; ±5V; 0-5V; 0-10V; 0-20mA; 4-20mA
■ ^{Data Acquisition systems}
■ ^{Motor control}
■ ^{Instrument and process control}
■ ^{Remote sensing}
■ ^{Programmable automation control}
Typical Application
LMP™ is a trademark of National Semiconductor Corporation.
© 2010 National Semiconductor Corporation 300755
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