Date: 13/03/2011

Current sense amplifier ICs with zero drift

The AD8218 is the latest zero-drift, bi-directional current-sense amplifier launched in the market by Analog Devices Inc (ADI). The AD8218 features a zero-drift core offering an offset drift of ± 100n V/°C over a -40 °C to +125 °C temperature range, while maintaining a typical small signal bandwidth of 500 kHz.

AD8218 features 20 V/V fixed gain with a maximum ±0.35 percent gain error over the entire temperature range. The AD8218 zero-drift precision amplifier's input common-mode can vary from 4 V to 80 V and includes a built-in reference for optimal dynamic range in unidirectional current monitoring or the ability to easily offset the output for bidirectional current sensing.

The AD8218 is designed into numerous high-side current-sensing signal chains, including base station, industrial motor control and computer power management applications. Another similar device from ADI is AD8217 high resolution, zero-drift current shunt monitor.

Key specifications and 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 (60 V/V AD8219)
Wide operating temperature range: -40 °C to +125 °C
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

Package: 8-lead MOSP
Price: Eack $1.05 per 1k pieces.