LMP8270, LMP8275

High Common Mode, Gain of 20, Precision Voltage

Difference Amplifiers

General Description

fiers with a -2V to 27V input common mode voltage range

and a supply voltage range of 4.5V to 5.5V. The LMP8270,

LMP8275 are precision amplifiers which will detect, amplify

and filter small differential signals in the presence of high

common mode voltages. The gain is fixed at 20 and is

adequate to drive an ADC to full scale in most cases. The

LMP8270, LMP8275 have a preamplifier with a fixed gain of

10 and an amplifier with a fixed gain of 2, achieving overall

fixed gain of 20. The internal signal path between these two

stages is brought out on two pins, A1 and A2, which provide

a connection for a filter network.

The LMP8270, LMP8275 will function with reduced specifi-

cations over the extended common mode input voltage

range of -5 to 36 Volts. This feature makes the device

suitable for applications with load dump in automotive sys-

tems.

Features

n

Typical Values, TA = 25˚C

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Input Offset Voltage

1mV max

n

TCVos (LMP8270)

15µV/˚C max

n

TCVos (LMP8275)

30µV/˚C max

n

CMRR

80dB Min

n

Extended CMVR

-5V to 36V

n

Output Voltage Swing

Rail to Rail

n

Bandwidth

80KHz

n

Operating Temperature Range (Ambient) -40˚C to 125˚C

n

Operating Temperature Range (bare die) -40˚C to 150˚C

n

Supply Voltage

4.5V to 5.5V

n

Supply Current

1mA

Applications

n

Fuel Injection Control

n

Low Side Driver Configuration Current Sensing

n

Power Management Systems

Typical Application

Typical Application: Low side Current Sensing

20130702

PRELIMINARY

January 2005

© 2005 National Semiconductor Corporation

DS201307

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