Latch Metastability Consider the problem of setting a latch when the data is late and/or has a very long rise/fall time and is still changing during t
{"Image DocumentName": "Latch Metastability", "Image ImageDescription": "Consider the problem of setting a latch when the data is late and/or has a very long rise/fall time and is still changing during the clock transition. if data change is delayed and overlaps clock edge (below), latch may set with new data rather than valid prior data. Data delay = 2.2 ns \uf0e0 latch sets correctly at Q=1. Data delay = 2.3 ns \uf0e0 latch hangs momentarily at metastable point, but then sets correctly at Q=1. Data delay = 2.4 ns \uf0e0 latch hangs momentarily and sets incorrectly at Q=0. Metastable point: non stable point in a latch where Vleft = Vright (neither 0 or 1 ) thermal noise will cause latch to move off metastable point and set at a 0 or a 1 How to fix? speedup the data (register-based synchronizer) delay the clock (introduce an intentional clock delay ---- risky!!) R. W. Knepper. SC571, page 5-53.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}