Improving Operational transconductance Amplifier (OTA) gain-bandwidth tradeoff using gate-underlap MOSFETs

The present work highlights the usefulness of underlap channel design in improving gain-bandwidth trade-off in analog circuit design. It is demonstrated that high values of intrinsic voltage gain (A_{VO_OTA}) > 55 dB and unity gain frequency (f_{T_OTA}) ~ 57 GHz of a folded cascode Operational transconductance Amplifier (OTA) can be achieved with gate-underlap channel design in 60 nm MOSFETs. These values correspond to a 15 dB improvement in A_{VO_OTA} and a 3 fold enhancement in f_{T_OTA} over a conventional non-underlap design. Gate-underlap OTA preserves functionality at high temperatures (550 K) by exhibiting high values of A_{VO_OTA} (42 dB) and f_{T_OTA} (24 GHz). Results present new opportunities for low voltage analog circuit design with future technologies.