HIGH-SPEED AND HIGH-ACCURACY DIGITAL-TO-ANALOG CONVERTER.

摘要

A high-speed, high-accuracy DAC has multiple current switches. Each current switchincludes a current source that provides a reference current, first and secondcircuit elements that couple to the current source, and first and second transistorsthat couple to the first and second circuit elements, respectively. The firsttransistor provides the reference current to a first output when enabled, andthe second transistor provides the reference current to a second output when enabled.The first and second circuit elements provide source degeneration for the firstand second transistors, extend the linear operating region for these transistors,and may be implemented with either transistors that are always turned on or resistors.The first and second transistors and the first and second circuit elements maybe P-channel field effect transistors (P-FETs), N-channel field effect transistors(N-FETs), or transistors of some other type.