Abstract: Current switches are arranged to reduce signal transit-time variations when they switch current signals that have a wide range of current magnitudes. The transit-time variations are reduced by shifting the range of currents that are carried by switching transistors. In particular, a current range is shifted upward to a higher current range in which the variation of the transistors' transition frequency fT is reduced. In general, the switches include a differential pair of transistors, an offset current source that generates an offset current and a current-steering system that steers the offset current along a current path that includes a switched-on transistor but excludes the output port of that transistor.

Abstract: Time-delay circuits are realized with first and second capacitors, a differential amplifier, a programmable current source and a differential pair of transistors. The current source directs first and second currents to the first and second capacitors and the differential pair steers a third current of the current source to either selected one of the capacitors to provide charging and discharging currents to the capacitors. The differential amplifier generates a delayed output pulse in response to voltages of the first and second capacitors. The capacitors are preferably formed by the interconnection system of an integrated circuit, i.e., the metallic circuit paths that are typically carried on an integrated-circuit substrate. N+1 of the delay circuits are combined with a phase comparator to form an interpolator that responds to an input data pulse by generating N output data pulses that span a period between the input data pulse and a successive input data pulse.