Comments, with reply, on 'Metastability of CMOS latch/flip-flop'

For the original article see ibid., vol.25, no.4, pp.942-951 (Aug. 1990). In the above titled paper L.-S. Kim and R.W. Dutton used SPICE small-signal circuit simulation (SPICE AC command) to evaluate a metastability performance parameter, tau , and compared several latch and flip-flop designs. They suggest that small-signal simulation is much easier to carry out than large-signal simulation for metastability studies and can be used to predict metastability performance. However, small-signal simulation is not sufficient to characterize metastability performance since it cannot determine a second parameter which is needed to determine synchronizer failure probability. In addition, Kim and Dutton make several errors in their use of small-signal simulation for determination of tau . The commenters present their own results that contrast with the original paper's conclusions, and discuss additional methods for determining tau . In their reply, Kim and Dutton acknowledge the commenters' points and go on to focus on how AC analysis can be used to extract the second parameter mentioned in the comment.<>