A 50 dB variable gain amplifier using parasitic bipolar transistors in CMOS

A variable-gain amplifier (VGA) with a gain range of 50 dB has been implemented in a standard 3 mu m CMOS process using parasitic lateral and vertical bipolar transistors to form the core of the circuit. The bipolar transistors had been characterized extensively. The VGA has a bandwidth larger than 3 MHz over the whole gain range and operates on a single 5 V power supply. The active area is about 0.8*0.9 mm/sup 2/.>