Wide Supply Range, Micropower, Rail-to-Rail Instrumentation Amplifier

The AD8420 is a low cost, micropower, wide supply range, instrumentation amplifier with a rail-to-rail output and a novel architecture that allows for extremely flexible design. It is optimized to amplify small differential voltages in the presence of large common-mode signals.

The AD8420 is based on an indirect current feedback architecture that gives it an excellent input common-mode range. Unlike conventional instrumentation amplifiers, the AD8420 can easily amplify signals at or even slightly below ground without requiring dual supplies. The AD8420 has rail-to-rail output, and the output voltage swing is completely independent of the input common-mode voltage.

Single-supply operation, micropower current consumption, and rail-to-rail output swing make the AD8420 ideal for battery-powered applications. Its rail-to-rail output stage maximizes dynamic range when operating from low supply voltages. Dual-supply operation (±15 V) and low power consumption make the AD8420 ideal for a wide variety of applications in medical or industrial instrumentation.

The AD8420 is available in an 8-lead MSOP package. Performance is specified over the full temperature range of −40°C to +85°C, and the part is operational from −40°C to +125°C

APPLICATIONS

* Bridge amplifiers

* Pressure Measurement

* Medical instrumentation

* Portable data acquisition

* Multichannel systems

* Maximum supply current:

90 μA

* Minimum CMRR: 100 dB

* Drives heavy capacitive loads:

~700 pF

* Rail-to-rail output

* Input voltage range goes below ground

* Gain set with 2 external resistors

Can achieve low gain drift at any gain

* Very wide power 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 voltage noise: 55 nV/√Hz

* See data sheet for additional features