A 1GHz, 68dB CMOS variable gain amplifier with an exponential-function circuit

A new wideband variable gain amplifier (VGA) is designed in digital 180nm CMOS technology for wideband and low-power application, such as UWB. The VGA consists of four stages of improved Cherry-Hooper amplifier cells, exponential function circuit and dc-offset cancellation (DCOC) network, which effectively reduces the output dc-offset. With an inductor-less technology and an additional exponential control circuit, a 3-dB bandwidth of more than 1GHz with 68dB tuning range is achieved by the proposed VGA, at the cost of 9.6mW power consumption and 0.19mm² chip area including pads.