A Novel Digital OTA Topology With 66-dB DC Gain and 12.3-kHz Bandwidth
Marco Privitera, Paolo Crovetti, Alfio Dario Grasso
Abstract
This brief introduces an enhanced digital OTA topology which allows increasing the DC gain thanks to the adoption of an inverter-based output stage. Moreover, a new equivalent small-signal model is proposed which allows to simplify the circuit analysis and paves the way to new frequency compensation strategies. Designed using a 28-nm standard CMOS technology and working at 0.3-V power supply, post-layout simulations show a 66-dB gain and a 12.3-kHz gain bandwidth product while driving a 250-pF capacitive load. As compared to other ultra-low-voltage OTAs in literature, an increase of small and large signal performance, respect to area occupation, equal to 4.6X and 1.5X, respectively, is obtained.