A low-voltage single input class AB transconductor with rail-to-rail input range

A new CMOS programmable rail-to rail transconductor is presented. A linear V-I characteristic is obtained by using the principle of nonlinearity cancellation of matched MOS transistors operating in the ohmic region. Rail-to-rail operation is achieved by using two complementary blocks. The circuit is suitable for low voltage as it can operate from supply voltages down to /spl plusmn/1.5 V. PSpice simulations show that the transconductance gain can be electronically tuned from 13 to 90 /spl mu/ A/V with bandwidth of about 40 MHz.