Latching characteristics of a CMOS bistable register

Closed-form solutions describing the output response of a CMOS bistable register are presented. From these results, the fundamental latching behavior of a CMOS register is developed in terms of its physical and circuit characteristics. Necessary and sufficient conditions for latching data are described in terms of small signal circuit parameters. From these necessary and sufficient conditions, the limiting requirement for latching, which provides the minimum let-up time and conditions for defining the onset of metastability, is presented and verified