Zero Drift, Bi-Directional Current Shunt Monitor

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 μV.

The AD8218 is offered in an 8-lead MSOP package.

Applications

High-side current sensing

* 48V telecom

* Power Management

* Base Stations

* Bidirectional motor control

Precision high voltage current sources

* 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