LMP8645/LMP8645HV

July 1, 2010

Precision High Voltage Current Sense Amplifier

General Description

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.

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.

Features

Typical values, T

— LMP8645

-2V to 42V

— LMP8645HV

-2V to 76V

2.7V to 12V

200 μA/V

1 mV

12 μA

90 dB

95 dB

−40°C to 125°C

Applications

Typical Application

30071632

LMP™ is a trademark of National Semiconductor Corporation.

© 2010 National Semiconductor Corporation

300716

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