A hybrid OTA with very wide gain adjustment range

A novel operating principle for CMOS operational transconductance amplifiers (OTAs) is presented. It is referred to as the hybrid OTA since the core of the transconductor operates in weak inversion while the shell operates in strong inversion. The technique allows very wide gain adjustment range, linearity improvement, and reduced quiescent power dissipation. Experimental results from a CMOS test chip are presented that verify the operating principle