A CMOS instrumentation amplifier with low voltage and low noise for portable ECG monitoring systems

A low voltage, low noise instrumentation amplifier (IA) applicable for Electrocardiogram signal acquisition system has been designed. The circuit is based on the current feedback topology which has been implemented using folded cascode structure at the input stage. It works at zero input common mode voltage with 1V supply. It has a wide input dynamic range of ±0.01mV to ±1.2mV. The voltage gain is 45dB and it consumes 165μW power. A high common mode rejection ratio (CMRR) of 125dB has been achieved. The integrated input referred noise is 3μV
rms
(0.2Hz – 150 Hz). The design has been done in 0.18μm standard CMOS process.