July 17, 2009
LMP8602/LMP8603
60V Common Mode, Fixed Gain, Bidirectional Precision
Current Sensing Amplifier
General Description
Features
The LMP8602 and LMP8603 are fixed gain precision ampli-
fiers. The parts will amplify and filter small differential signals
in the presence of high common mode voltages. The input
common mode voltage range is –22V to +60V when operating
from a single 5V supply. With a 3.3V supply, the input com-
mon mode voltage range is from –4V to +27V. The LMP8602
and LMP8603 are members of the Linear Monolithic Precision
(LMP®) family and are ideal parts for unidirectional and bidi-
rectional current sensing applications. All parameter values
of the parts 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 = 50x (LMP8602), Gain = 100x (LMP8603)
TCVos
10μV/°C max
90 dB min
1 mV max
−4V to 27V
−22V to 60V
■
■
■
■
■
■
■
■
CMRR
Input offset voltage
CMVR at VS = 3.3V
CMVR at VS = 5.0V
Operating ambient temperature range −40°C to 125°C
Single supply bidirectional operation
All Min / Max limits 100% tested
The parts have a precise gain of 50x for the LMP8602 and
100x for the LMP8603, which are adequate in most targeted
applications to drive an ADC to its full scale value. The fixed
gain is achieved in two separate stages, a preamplifier with a
gain of 10x and an output stage buffer amplifier with a gain of
5x for the LMP8602 and 10x for the LMP8603. The connection
between the two stages of the signal path is brought out on
two pins to enable the possibility 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 applications section.
Applications
High side and low side driver configuration current sensing
■
■
■
■
■
■
Bidirectional current measurement
Current loop to voltage conversion
Automotive fuel injection control
Transmission control
Power steering
Battery management systems
■
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.
The LMP8602 and LMP8603 are available in a 8–Pin SOIC
package and in a 8–Pin MSOP package.
Typical Applications
30083401
LMP™ is a trademark of National Semiconductor Corporation.
© 2009 National Semiconductor Corporation
300834
www.national.com