900 mV differential class AB OTA for switched opamp applications

Abstract

A novel fully differential class AB OTA in standard CMOS for application with the switched opamp technique is presented. It makes use of a current buffer loop in the input stage as a low voltage current mirror. A new common mode feedback error amplifier, especially suited for the class AB OTA, is also presented. It is based on a differential stage of which the concept is introduced here. A totally new way of switching the amplifiers is introduced as well. Simulations demonstrate the operation of these novel circuits down to a 900 mV supply voltage.