:PROPERTIES: :ID: 6ca6a52c-d402-4b9b-a45a-892599375754 :mtime: 20231023030611 20231020034957 :ctime: 20231020034955 :END: #+title: meta-stability #+filetags: :public:project: * Definition of Meta-Stability *meta-stability* refers to an intermediate condition that is temporarily stable. It is an unstable equilibrium. Imagine a ball resting on top of a hill. A ball at the bottom of a hill is stable, but a ball resting on top of a hill is meta-stable. * Meta-stability in Digital Electronics See [[id:894f2262-5a61-48dc-a229-4f767f68493e][Meta-stability in Digital Electronics.]] - It is not always possible to control when a [[id:2c4ec126-9394-40b4-82e0-209cd3501c4b][flip-flop]] input changes in relation to the [[id:8373651b-39e3-4772-90c3-7ac5079a1e8f][clock edge]] - For example, this can occur when the input signal comes from an external user input, e.g., a button - Consider the following example when the D input change violates the dynamic requirements - This causes the output Q to be undefined - Momentarily it can take on a voltage between 0 and VDD , i.e., in the invalid range