同步寄存器(Synchronizer)和“打两拍”(Two flip-flop synchronizer) 打两拍并不能完全消除亚稳态。 打两拍并不意味着能正确采样。 MTBF(Mean Time Between Failure)平均失效间隔时间 C1和 C2是常数,依赖于器件工艺和操作环境。 fCLK和 fDATA参数取决于设计规格: fCLK是接收异步信号的时钟域的时钟频率,fDATA是异...
使用同步电路以后,亚稳态仍然有发生的可能,与此相连的是MTBF(Mean Time Between Failure),亚稳态的发生概率与时钟频率无关,但是MTBF与时钟有密切关系。有文章提供了一个例子,某一系统在20MHz时钟下工作时,MTBF约为50年,但是时钟频率提高到40MHz时,MTBF只有1分钟!可见降低时钟频率可以大大减小亚稳态导致系统错误的...
5.亚稳态与系统可靠性 使用同步电路以后，亚稳态仍然有发生的可能，与此相连的是平均故障间隔时间MTBF（mean time between failure），亚稳态的发生概率与时钟频率无关，但是 MTBF与时钟有密切关系。 有文章提供了一个例子，某一系统在 20MHz 时钟下工作时，MTBF约为 50年，但是时钟频率提高到 40MHz...
I am not looking here to derive MTBF equation :-) So how do I avoid metastability? In reality, one cannot avoid metastability and increased clock-to-Q delays in synchronizing asynchronous inputs, without the use of tricky self-timed circuits. So a more appropriate question might be "How do...
A dual model of the metastability distinguishes two transitions at the flip–flop output (L/H and H/L) which have different impact on the Mean Time Between Failures (MTBF) of the flip–flop. A new circuit of the late transition detector (LTD) allows for determination of the pairs of the...
The evaluation of the MTBF (Mean Time Between Failure) characteristics of PLD is done, based on the propagation delay distribution measurement of bistable output in the circumstances of deliberately inducing metastable behaviour. The testing results help in design, examine and to predict required MTBF...
If the design uses only the Auto Synchronizer Identification setting, the reports list likely synchronizers but do not report MTBF. To obtain an MTBF for each register chain you must force identification of synchronization registers. If the synchronizer chain does not meet its timing requirements, ...
3.2. Metastability and MTBF Reporting 3.2.1. Metastability Reports 3.2.1.1. MTBF Summary Report 3.2.1.2. Synchronizer Summary Report 3.2.1.3. Synchronizer Chain Statistics Report in the Timing Analyzer 3.2.2. Synchronizer Data Toggle Rate in MTBF Calculation ...
Calculating Metastability MTBF The mean time between failures, or MTBF, due to metastability provides an estimate of the average time between instances when metastability could cause a design failure. A higher MTBF (such as hundreds or thousands of years between metastability failures) indicates a ...
Exorcise metastability from your design. (includes related articles on manager knowledge of metastability, characterizing metastability and hw to estimate mean time between failure (MTBF)) (Tutorial)Shear, David