A 15 GHz, 1.8V, variable-gain, modified Cherry-Hooper amplifier

This paper describes the design of an inductor-less variable-gain amplifier cell with a bandwidth over 15 GHz. A high bandwidth is maintained even when the amplifier cells are cascaded, for example in implementing a limiting amplifier. The amplifier cell is implemented using a modified Cherry-Hooper architecture that utilizes active negative feedback to obtain a variable gain from -4 to +17dB for 16 cascaded cells, and an adjustable bandwidth from 9GHz to 15GHz per cell with a nominal bandwidth of 12.4GHz. By avoiding the use of broadbanding techniques, such as peaking inductors, area is greatly reduced. The optimized amplifier cell occupies an area of 93/spl mu/m by 42/spl mu/m, and is critically damped to limit peaking to 0dB.