Over rail-to-rail fully differential voltage-to-current converters for nm scale CMOS technology

The converters presented in this paper are based on long channel complementary MOS transistors, instead of the commonly used differential amplifiers or differential transistor pairs which are difficult to implement in low voltage, nm scale CMOS technology. Nonlinearities of drain currents can be cancelled in the fully differential structure. As a result, the low power, nanometre standard digital CMOS technology converters are obtained. Layout examples are designed in 65 nm TSMC technology. Post-layout simulations show that the range of input voltage over rail-to-rail is achieved with very good linearity and reduced harmonic distortion.