An interleaved delay line for use in phase locked and delay locked loops is comprised
of a first portion providing a variable amount of delay substantially independently
of process, temperature and voltage (PVT) variations while a second portion, in
series with the first portion, provides a variable amount of delay that substantially
tracks changes in process, temperature, and voltage variations. By combining, or
interleaving, the two types of delay, single and dual locked loops constructed
using the present invention achieve a desired jitter performance under PVT variations,
dynamically track the delay variations of one coarse tap without a large number
of delay taps, and provide for quick and tight locking. Methods of operating delay
lines and locked loops are also disclosed.
