0.6-V CMOS bulk-driven instrumentation amplifier for IoMT bioimpedance analysis

An instrumentation amplifier (IA), aimed at wideband bioimpedance analysis in the low-voltage low-power scenario of internet of medical things (IoMT), is presented. The operation principle is based on the indirect current feedback technique, where an input and a feedback transconductor determine the voltage gain of the preamplifier. The required transconductors consist of two bulk-driven flipped-voltage-follower cells and an active pseudo-resistor, thus leading to a linear and compact implementation. The circuit has been designed and fabricated in 180 nm CMOS technology to operate with a 0.6-V supply. Experimental results obtained from measurements on eight samples of the silicon prototype show that when the IA is programmed to have a nominal voltage gain of 11 V/V, the bandwidth is 316.2 kHz, the CMRR exceeds 63 dB, and the maximum output voltage that can be processed with a THD below -40 dB is 555 mV pp$$ {}_{pp} $$. An instrumentation amplifier aimed at wideband bioimpedance analysis in the low-voltage low-power scenario of internet of medical things and supplied with 0.6 V is presented. Experimental results in 180 nm CMOS technology are provided. image