A direct-skew-detect synchronous mirror delay for application-specific integrated circuits

A nonfeedback CMOS digital-clock-generator, direct-skew-detect synchronous-mirror-delay (direct SMD) circuit has been developed that achieves clock-skew suppression in only two clock cycles for application-specific integrated circuits having unfixed and various clock paths. The direct SMD circuit detects both clock skew and clock cycle by using a direct-skew detector and clock-suspension circuitry. The skew-detection scheme removes the phase errors caused by delay in the clock-driver circuit. Measurements demonstrated that the direct SMD circuit eliminates various amounts of clock skew (2.0-3.0 ns) at 200 MHz in two clock cycles.