CIRCUIT FOR PRODUCING LOW-VOLTAGE DIFFERENTIAL SIGNALS

摘要

Described are systems for producing differential logic signals. These system s can be adapted for use with different loads by programming one or more programmable elements. One embodiment includes a series of driver stages, th e outputs of which are connected to one another. The driver stages turn on successively to provide increasingly powerful differential amplification. Th is progressive increase in amplification produces a corresponding progressive decrease in output resistance, which reduces the noise associated with signa l reflection. The systems can be incorporated into programmable IOBs to enable PLDs to provide differential output signals.