A simple high frequency CMOS transconductor

Abstract

A transconductor utilizing only two transistors is presented. It is based upon standard inverter configurations and does not need matching of NMOS and PMOS transistors or of the power supply voltages. The reduction in nonlinearity is achieved by maintaining a zero offset condition. The circuit is not affected by variations in body effect as sources and substrates are connected to fixed voltages. Although the inverter has a low signal level handling capability ( approximately=300 mV for a total harmonic distortion of 1%), it can be improved by utilizing two inverters. This leads to a larger dynamic range and has no noticeable effect on the bandwidth. On the basis of this transconductor, a wideband integrator is developed, with independent adjustment of quality factor and unity-gain frequency.<>