Dynamic vs Static Timing Analysis

Dynamic vs Static Timing Analysis

Timing analysis is integral part of ASIC/VLSI design flow. Anything else can be compromised but not timing! Timing analysis can be static ordynamic. Dynamic timing analysis verifies functionality of the design by applying input vectors and checking for correct output vectors whereas Static Timing Analysis checks static delay requirements of the circuit without any input or output vectors.

Dynamic timing analysis has to be accomplished and functionality of the design must be cleared before the design is subjected to Static Timing Analysis (STA). Dynamic Timing Analysis (DTA) and Static Timing Analysis (STA) are not alternatives to each other. Quality of the Dynamic Timing Analysis (DTA) increases with the increase of input test vectors. Increased test vectors increase simulation time. Dynamic timing analysis can be used for synchronous as well as asynchronous designs. Static Timing Analysis (STA) can’t run on asynchronous deigns and hence Dynamic Timing Analysis (DTA) is the best way to analyze asynchronous designs. Dynamic Timing Analysis (DTA) is also best suitable for designs having clocks crossing multiple domains.

Example of Dynamic Timing Analysis(DTA) tool is Modelsim (from mentor Graphics), VCS (from Synopsys). DTA is also carried out on post layout netlist to verify that functionality of the design has not changed. Test vectors remain same for both.