SIMPLE HIGH-FREQUENCY CMOS TRANSCONDUCTOR

A new transconductor, using only two transistors, is presented. It is based on standard inverter configurations and does not need matching of nMOS and pMOS transistors or of the power supply voltages. 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 (≅ mV for a total harmonic distortion of 1%), this can be improved by the use of two inverters. This leads to a larger dynamic range and has no noticeable effect on bandwidth. A wideband integrator is developed, based on the new transconductor, with independent adjustment of quality factor and unity-gain frequency.