Dual-edge late-transition detector for testing the metastability effect in flip-flops

A method for determination of the metastability parameters W and /spl tau/ of flip-flops is described. The presented late-transition detector (LTD) allows for the estimation of metastability effects appearing at both types of propagation times in flip-flops (t/sub pl.H/ and t/sub pHL/) and calculation of two relevant measures of the mean time between failures (MTBF), which can be combined into a single value. The method is illustrated with the tests of four types of programmable logic devices. We used the PC-controlled test setup with dedicated test fixtures, HP-IB interface, and HP VEE software.