A Method for Skew-free Distribution of Digital Signals Using Matched Variable Delay Lines

Abstract

The ability to distribute signals everywhere in a circuit with controlled and known delays is essential in large, high-speed digital systems. We present a technique by which a signal driver can adjust the arrival time of the signal at the end of the wire using a pair of matched variable delay lines. We show an implemention of this idea requiring no extra wiring, and how it can be extended to distribute signals skew-free to receivers along the signal run. We demonstrate how this scheme fits into the boundary scan logic of a VLSI chip.