Instrumentation Amplifier Combines Precision, Power Efficiency & Value For Battery-Powered Medical, Instrumentation & Consumer Devices



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Providing a unique combination of precision, low power and value, Analog Devices, Inc. (ADI) introduced today the AD8420 micropower, wide-supply-range instrumentation amplifier -- the newest addition to its award-winning instrumentation amplifier product line. The AD8420 features a high CMRR (common-mode rejection ratio) of 100 dB while consuming 75 uA of power, which provides designers with improved signal quality and longer battery life compared to competitive offerings. The amplifier's high CMRR makes it well suited for bridge amplifiers, pressure sensing and similar uses, allowing designers to greatly improve signal quality and overall system performance in portable and battery-powered precision signal healthcare and instrumentation applications such as infusion pumps, remote and handheld metering equipment and smart phones.

The AD8420 has excellent dc performance with 200 uV of input offset and 1 uV/°C of offset drift, with improved performance available in the advanced grade AD8420B model. The AD8420 supports rail-to-rail operation on the output with a wide input-voltage range that allows it to amplify signals below supply ground. The gain (1 to 1000) is set by the ratio of two external resistors, providing better gain accuracy over temperature. The AD8420 features a wide 2.7-V to 36-V single and +/-18-V dual-power supply range and ships in a compact MSOP-8 package. This blend of performance, power, and small size is available for 89 cents in 1,000-unit volumes. AD8420 Micropower Wide-supply-range Instrumentation Amplifier Key Features:
  • Gain range: 1 to 1000
  • CMRR: 100 dB
  • Supply Current: 75 uA
  • Wide Supply Range
  • Single supply: 2.7 V to 36 V
  • Dual supply: +/-2.7 V to+/-18 V
  • Bandwidth (G=100): 2.5 kHz
  • Input noise: 50 nV/?Hz
  • Max offset voltage: 200 uV
  • Max offset drift: 1uV/C
The AD8420 operates well in a system with a variety of SAR A/D Converters like the AD7298-1 and the AD7291.