A folded-cascode switched OTA based on current deviation

An improved version of a fully differential folded-cascode OTA (operational transconductance amplifier), switched at 16 MHz with a single 3 V supply voltage, is presented. The switching process is performed by current deviation at the OTA output stage, instead of turning off its bias current or interrupting the current path from the power supply. Theoretical results show the relationship between the sampling frequency and the folded-cascode OTA design parameters. Simulated results using HSPICE show that the current through the transistors at the OTA output stage is switched properly.