Slew-rate limited differential driver with improved skew control

摘要

Slew-rate limited differential drivers are useful for reliable data transmission on longer un-terminated cables with longer stub lengths. Slew-rate limit can be achieved by the ratio of a constant current to a capacitor means. In order to have equal rise and fall times, an equal amount of current is steered into the capacitor means in opposite directions. This architecture has unequal propagation delays on the transition edges. This mismatch is directly attributable to the signal transfer in current steering means. The slew-rate limited differential driver corrects this problem by delaying the rising edge by the required amount using a second capacitor means and a diode means. And hence, the preferred embodiment has a better skew on the output.