Method and apparatus for temperature compensating a digital to analog converter

摘要

A current-source ladder digital-to-analog converter is compensated for temperature changes by making the total current running through the converter proportional to absolute temperature and by terminating the parallel transistor chain forming the current source ladder with a transistor whose emitter voltage is greater than the emitter voltage of the least significant bit current source transistor by 2(KT/q)ln 2 volts. The aformentioned voltage difference is achieved by making the emitter area of the termination transistor at least eight times the emitter area of the least significant bit transistor.