Multi mode multi corner analysis

Multi mode multi corner analysis

 Introduction to MCMM:

Multi-mode multi-corner (MMMC) analysis refers to performing STA across multiple operating modes, PVT corners and parasitic interconnect corners at the same time. For example, consider a DUA that has four operating modes (Normal, Sleep, Scan shift, Jtag), and is being analyzed at three PVT corners (WCS, BCF, WCL) and three parasitic interconnect corners (Typical, Min C, Min RC) as shown in Table 3.1

Pvt corner/ Parasitic corners	WCS	BCF	WCL
Typical	1: Normal/sleep/scan shift/Jtag	2 :Normal/sleep/scan shift	3:Normal/sleep
Min C	4: not required	5:Normal/sleep	6: not required
Min RC	7: not required	8:Normal/sleep	9: not required

Table 3.1: possible scenarios

There are a total of thirty six possible scenarios at which all timing checks, such as setup, hold, slew, and clock gating checks can be performed. Running STA for all thirty six scenarios at the same time can be prohibitive in terms of runtime depending upon the size of the design. It is possible that a scenario may not be necessary as it may be included within another scenario, or a scenario may not be required. For example, the designer may determine

that scenarios 4, 6, 7 and 9 are not relevant and thus are not required. Also, it may not be necessary to run all modes in one corner, such as Scan shift or Jtag modes may not be needed in scenario 5. STA could be run on a single scenario or on multiple scenarios concurrently if multi-mode multicorner capability is available.