Low-distortion, emitter-coupled, differential voltage-to-current converters

This paper considers two schemes in which negative feedback is applied to a conventional emitter-coupled differential voltage-to-current converter circuit in order to achieve lower distortion. Representative circuits for each of these schemes together with simulated results for a given value of emitter-degeneration resistor are presented. It is possible to achieve a reduction in total harmonic distortion (THD) exceeding 20dB, for a peak-to-peak differential input voltage of 500mV, over that possible without this feedback.