Publication:

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

An instrumentation amplifier (IA), aimed at wideband bioimpedance analysisin the low-voltage low-power scenario of internet of medical things (IoMT), ispresented. The operation principle is based on the indirect current feedbacktechnique, where an input and a feedback transconductor determine thevoltage gain of the preamplifier. The required transconductors consist of twobulk-driven flipped-voltage-follower cells and an active pseudo-resistor, thusleading to a linear and compact implementation. The circuit has been designedand fabricated in 180 nm CMOS technology to operate with a 0.6-V supply.Experimental results obtained from measurements on eight samples of thesilicon prototype show that when the IA is programmed to have a nominalvoltage gain of 11 V/V, the bandwidth is 316.2 kHz, the CMRR exceeds63 dB, and the maximum output voltage that can be processed with a THDbelow –40 dB is 555 mVpp.