On-chip circuit for measuring jitter and skew with picosecond resolution

A circuit for on-chip measurement of long-term jitter, period jitter, and clock skew, is demonstrated. The circuit uses a single latch and a voltage-controlled delay element, and is evaluated in a stand-alone pad frame. Excellent reproduction of jitter measured by oscilloscope is shown. Measured jitter resolution is 1 ps or better. The circuit is also incorporated into a 2 GHz clock distribution network to obtain on-chip period jitter and clock skew measurements.