A new delay generator based on a series of coupled
ring oscillators has been developed; it produces precise delays
with subgate delay resolution for chip testing applications. It
achieves a delay resolution equal to a buffer delay divided by the
number of rings. The coupling employed forces the outputs of a
linear array ofringoscillators oscillating at the same frequency
to be uniformly offset in phase by a precise fraction of a buffer
delay. The buffer stage used in the ring oscillators is based on
a source-coupled pair and achieves high supply noise rejection
while operating at low supply voltages. Experimental results from
a 2-#m N-well CMOS implementation of the delay generator
demonstrate that it can achieve an output delay resolution of
101 ps while operating at 141 MHz with a peak error of 58 ps.
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Editorial
Upcoming Events
DAC 2012 at San Francisco CA - Jun 3 - 7, 2012
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