Accurate micropower class AB CMOS voltage-to-current converter

A CMOS voltage-to-current converter is presented. It is based on a class AB current mirror with very low input resistance and a passive resistor connected to the input for voltage-to-current conversion. Class AB operation is achieved without extra supply voltage requirements or static power consumption, using Quasi-Floating Gate techniques. Measurement results of a differential configuration for a 0.5μm CMOS test chip prototype are presented. A measured harmonic distortion at 1MHz of -59dB is achieved for current signals 20 times larger than the bias currents. The circuit consumes 265μW using a supply voltage of ±1.65V and requires a silicon area of 0.04mm².