Precision, Dual-Channel Instrumentation Amplifier

The AD8222 is a dual-channel, high performance instrumentation amplifier that requires only one external resistor per amplifier to set gains of 1 to 10,000.

The AD8222 is the first dual-instrumentation amplifier in the small 4 mm × 4mm LFCSP. It requires the same board area as a typical single instrumentation amplifier. The smaller package allows a 2× increase in channel density and a lower cost per channel, all with no compromise in performance.

The AD8222 can also be configured as a single-channel, differential output instrumentation amplifier. Differential outputs provide high noise immunity, which can be useful when the output signal must travel through a noisy environment, such as with remote sensors. The configuration can also be used to drive differential input analog-to-digital converters (ADCs). The AD8222 maintains a minimum CMRR of 80 dB to 4 kHz for all grades at G = 1. High CMRR over frequency allows the AD8222 to reject wideband interference and line harmonics, greatly simplifying filter requirements. The AD8222 also has a typical CMRR drift over temperature of just 0.07 µV/V/°C at G = 1.

The AD8222 operates on both single and dual supplies and only requires 2.2 mA maximum supply current for both amplifiers. It is specified over the industrial temperature range of −40°C to +85°C and is fully RoHS compliant.

For a single-channel version, see the AD8221.

Applications

* Multichannel data acquisition for

* ECG and medical instrumentation

* Industrial process controls

* Wheatstone bridge sensors

* Differential drives for

* High resolution input ADCs

* Remote sensors

* Two channels in small 4 mm × 4 mm LFCSP

* Gain set with 1 resistor per amplifier (G = 1 to 10,000)

* Low noise

* 8 nV/√Hz at 1 kHz

* 0.25 µV p-p (0.1 Hz to 10 Hz)

* High accuracy dc performance (B grade)

* 60 µV maximum input offset voltage

* 0.3 µV/°C maximum input offset drift

* 1.0 nA maximum input bias current

* 126 dB minimum CMRR (G = 100)

* Excellent ac performance

* 140 kHz bandwidth (G = 100)

* 13 µs settling time to 0.001%

* Differential output option (single channel)

* Fully specified

* Adjustable common-mode output

* Supply range: ±2.3 V to ±18 V