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

Abstract

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 mm2 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.

Keywords

• Ultra-low voltage (ULV) CMOS
• ultra-low power (ULP)
• operational transconductance amplifier (OTA)
• digital-based circuit
• the Internet of Things (IoT)