Zero Drift, Bidirectional
Data Sheet
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FEATURES
High common-mode voltage range
4 V to 80 V operating
−0.3 V to +85 V survival
Buffered output voltage
Gain = 20 V/V
Wide operating temperature range: −40°C to +125°C
Excellent ac and dc performance
±100 nV/°C typical offset drift
±50 µV typical offset
±5 ppm/°C typical gain drift
110 dB typical CMRR at dc
APPLICATIONS
High-side current sensing
48 V telecom
Power management
Base stations
Bidirectional motor control
Precision high voltage current sources
FUNCTIONAL BLOCK DIAGRAM
LDO
R2
R1
AD8218
R4
R3
+IN
–IN
OUT
ENB
REF
GND
V
S
09592-001
Figure 1.
GENERAL DESCRIPTION
The AD8218 is a high voltage, high resolution current shunt
amplifier. It features a set gain of 20 V/V, with a maximum
±0.35% gain error over the entire temperature range. The
buffered output voltage directly interfaces with any typical
converter. The AD8218 offers excellent input common-mode
rejection from 4 V to 80 V. The AD8218 performs bidirectional
current measurements across a shunt resistor in a variety of
industrial and telecom applications, including motor control,
battery management, and base station power amplifier bias
control.
The AD8218 offers breakthrough performance throughout the
−40°C to +125°C temperature range. It features a zero-drift core,
which leads to a typical offset drift of ±100 nV/°C throughout
the operating temperature range and the common-mode voltage
range. Special attention is devoted to output linearity being
maintained throughout the input differential voltage range of
0 mV to ~250 mV. The AD8218 also includes an internal 80 mV
reference that can be enabled for optimal dynamic range in
unidirectional current sense applications. The typical input
offset voltage is ±50 µ V.
The AD8218 is offered in an 8-lead MSOP package and an
8-lead LFCSP package.
