Micropower integrated bioamplifier and auto-ranging ADC for wireless and implantable medical instrumentation

A micropower, high-resolution biopotential data acquisition circuit for wireless and implantable medical instrumentation is presented. The circuit is an incremental ΔΣ (BioADC) that accepts inputs directly from recording electrodes and serves as both amplifier and digitizer with just a single OTA at the core. Auto-ranging and precise digital gain control allow the BioADC to accommodate input ranges of 1mV to 30mV with DC offset rejection. The hybrid amplifier/ADC achieves up to 12 bits of resolution, a sampling rate of 2.048kHz and an input referred noise of 2.65μVrms at a power consumption of 20/μW. The bioamplifier achieves a noise efficiency factor of 3.1. Live physiological ECG data are shown, acquired by connecting passive Ag/AgCl electrodes directly to the BioADC input.