July 1, 2010
LMP8645/LMP8645HV
Precision High Voltage Current Sense Amplifier
General Description
Features
The LMP8645 and the LMP8645HV are precision current
sense amplifiers that detect small differential voltages across
a sense resistor in the presence of high input common mode
voltages with a supply voltage range from 2.7V to 12V.
Typical values, TA = 25°C
High common-mode voltage range
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LMP8645
LMP8645HV
Supply voltage range
-2V to 42V
-2V to 76V
2.7V to 12V
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The LMP8645 accepts input signals with common mode volt-
age range from -2V to 42V, while the LMP8645HV accepts
input signal with common mode voltage range from -2V to
76V. The LMP8645 and LMP8645HV have adjustable gain
for applications where supply current and high common mode
voltage are the determining factors. The gain is configured
with a single resistor, providing a high level of flexibility, the
accuracy could be as low as 2% (max) including the gain set-
ting resistor. The output is buffered in order to provide low
output impedance. This high side current sense amplifier is
ideal for sensing and monitoring currents in DC or battery
powered systems, excellent AC and DC specifications over
temperature, and keeps errors in the current sense loop to a
minimum. The LMP8645 is an ideal choice for industrial, au-
tomotive and consumer applications, and it is available in
TSOT-6 package.
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Gain configurable with a single resistor
Max variable gain accuracy (with external resistor) 2.0%
Transconductance
Low offset voltage
Input bias
PSRR
CMRR
Temperature range
6-Pin TSOT Package
200 μA/V
1 mV
12 μA
90 dB
95 dB
−40°C to 125°C
Applications
High-side current sense
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Vehicle current measurement
Motor controls
Battery monitoring
Remote sensing
Power management
Typical Application
30071632
LMP™ is a trademark of National Semiconductor Corporation.
© 2010 National Semiconductor Corporation
300716
www.national.com