A delay locked loop clock generation circuit (100) includes a delay locked
loop circuit (18), a dummy delay line (40), and a watch dog circuit
(32). The delay locked loop circuit includes a delay line (20), a
phase detector (25), and a charge pump circuit (30) having an input
connected to the output (27) of the phase detector and an output (23)
producing a delay control signal (Vctrl) coupled to the stages of the delay line
of the delay locked loop circuit. The stages of the delay line are precisely matched
to those of the dummy delay line (40). Tap points of the dummy delay line
are connected to inputs of the watchdog circuit (32), which operates to
generate control signals (34A,B) applied to control the phase detector (25
and the charge pump circuit (30). Tap point signals of the delay line (20)
are decoded to produce clock signals (52) for a pipeline ADC (54).