A High-Input Impedance Chopper Capacitively Coupled Instrumentation Amplifier With DC Offset Compensation

An improved chopper capacitively coupled instrumentation amplifier (CCIA) is proposed for electrocardiogram (ECG) signal acquisition applications. Impedance boosting techniques improve the input impedance. The direct current servo loop (DSL) along with a programmable DC offset compensation module suppresses electrode offset. The CCIA, fabricated in 0.18μm CMOS, achieves an input impedance of 2.2GΩ and suppresses electrode offset up to 230mV under 1.8V supply. The input-referred noise of 1.4 μVrms is measured with 2.07 μW power consumption.