Micropower Class-AB VGA With Gain-Independent Bandwidth

A novel class-AB variable gain amplifier with constant bandwidth and continuous gain tuning is presented. It is based on the cascade connection of a tunable transconductor and a transresistance amplifier. Class-AB operation is achieved using quasi-floating gate transistors. The circuit has been fabricated in a 0.5- μm CMOS technology, showing a third-order input intercept point (IIP3) of 13 dBV p for a power consumption of 500 μW.