July 16, 2009
LMP8601/LMP8601Q
60V Common Mode, Bidirectional Precision Current
Sensing Amplifier
General Description
Features
The LMP8601 and LMP8601Q are fixed 20x gain precision
amplifiers. The part will amplify and filter small differential sig-
nals in the presence of high common mode voltages. The
input common mode voltage range is –22V to +60V when op-
erating from a single 5V supply. With 3.3V supply, the input
common mode voltage range is from –4V to +27V. The
LMP8601 and LMP8601Q are members of the Linear Mono-
lithic Precision (LMP®) family and are ideal parts for unidirec-
tional and bidirectional current sensing applications. All
parameter values of the part that are shown in the tables are
100% tested and all bold values are also 100% tested over
temperature.
Unless otherwise noted, typical values at TA = 25°C,
VS = 5.0V, Gain = 20x
TCVOS
CMRR
10μV/°C max
90 dB min
1 mV max
−4V to 27V
−22V to 60V
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Input offset voltage
CMVR at VS = 3.3V
CMVR at VS = 5.0V
Operating ambient temperature range −40°C to 125°C
LMP8601Q available in Automotive AEC-Q100 Grade 1
qualified version
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Single supply bidirectional operation
All Min / Max limits 100% tested
The part has a precise gain of 20x which is adequate in most
targeted applications to drive an ADC to its full scale value.
The fixed gain is achieved in two separate stages, a pream-
plifier with a gain of 10x and an output stage buffer amplifier
with a gain of 2x. The connection between the two stages of
the signal path is brought out on two pins to enable the pos-
sibility to create an additional filter network around the output
buffer amplifier. These pins can also be used for alternative
configurations with different gain as described in the applica-
tions section .
Applications
High side and low side driver configuration current sensing
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Bidirectional current measurement
Current loop to voltage conversion
Automotive fuel injection control
Transmission control
Power steering
The mid-rail offset adjustment pin enables the user to use
these devices for bidirectional single supply voltage current
sensing. The output signal is bidirectional and mid-rail refer-
enced when this pin is connected to the positive supply rail.
With the offset pin connected to ground, the output signal is
unidirectional and ground-referenced .
Battery management systems
The LMP8601Q incorporates enhanced manufacturing and
support processes for the automotive market, including defect
detection methodologies. Reliability qualification is compliant
with the requirements and temperature grades defined in the
AEC Q100 standard.
Typical Applications
20157101
LMP™ is a trademark of National Semiconductor Corporation.
© 2009 National Semiconductor Corporation
201571
www.national.com