A fully tunable large-signal linear MOS transconductor design using linear composite-MOSFETs

The limitations of a general MOS differential pair transconductor architecture are briefly reviewed, and a tunable scheme for linear transconductance design which allows independent tuning of its transconductance and its output impedance simultaneously within the same cell is proposed. To implement this full tuning capability, a suitable circuit in MOS technology is the linear composite-MOSFET (COMFET) proposed by the authors (1991). Although the COMFET realization described is nonoptimum, it serves to demonstrate the principle.<>