Low-Voltage, Low-Area, nW-Power CMOS Digital-Based Biosignal Amplifier

This paper presents the operation principle and the silicon characterization of a power efficient ultra-low voltage and ultra-low area fully-differential, digital-based Operational Transconductance Amplifier (OTA), suitable for microscale biosensing applications (BioDIGOTA). Measured results in 180nm CMOS prototypes show that the proposed BioDIGOTA is able to work with a supply voltage down to 400 mV, consuming only 95 nW. Owing to its intrinsically highly-digital feature, the BioDIGOTA layout occupies only 0.022 mm
²
of total silicon area, lowering the area by
$3.22\times $
times compared to the current state of the art, while keeping reasonable system performance, such as 7.6 NEF with
$1.25~\mu V_{\mathrm {RMS}}$
input referred noise over a 10 Hz bandwidth, 1.8% of THD, 62 dB of CMRR and 55 dB of PSRR.