A Wide Range Constant Transconductance Circuit Based on Negative Feedback for Analog Circuits

This paper presents a fixed transconductance circuit based on the impedance matching. The proposed technique does not depend on the square law model of the transistors and tracks the resistor for all operating regions of the transistor. Unlike its predecessors, the transconductance of the transistor tracks for a wide range of external resistors. Such techniques find applications in analog and mixed-signal circuits like data converters, voltage-controlled oscillators, amplifiers, etc. The proposed circuit is implemented in the TSMC 65nm LP process, and it occupies an area of 55 mu m x 2 mu pm. The transconductance varies about 0.8% over a nominal value of 125 mu S across process corners and temperature. Monte Carlo simulation results show a standard deviation of 4.64 mu S over a mean of 125.8 mu S.