Post layout transient simulation

not to ask a silly question, but why find Vx and add vds_M2 instead of just finding vdda directly?  Or is this because of L or R extraction on a net and you want to measure right by the transistor?  One issue is VT() is for node voltages.  You want OPT() for transient operating point so use the same thing you have for OP() for dc operating point but OPT().  If that doesn't work then you likely are missing a save option.

Dear delgsy,

delgsy said:

My plan was by adding Vx and vds_M2 which works in DC, but not in transient.
It is because there is no transient result of vds_M2 in result browser.
Is there any tips or work around for this?

As drdanmc also suggested, I believe you have not saved the transient signal of interest. I am unable to view the exact expression in your save statement adjacent the "eval err". However, the "vds" nomenclature is reserved for an operating point of an MOS device as shown in Figure 1 and not a signal net.

1. To save the vds of the MOS device, you need to define the difference in the saved drain and source voltages as a signal expression in Assembler/Explorer. Ensuring you have this defined as an output save statement will allow you to plot it following your transient analysis.

2. The list of signal access functions, other than the more generic getData() function, can be found from the Calculator. Hovering your mouse over each will show you which access function is designed for which analysis type. In Figure 2, I show the result when my mouse hovers over the vt radio button.

I just hope I understood your question delgsy -  and this provides a little insight. 

Shawn

Figure 1:

Reference: https://support.cadence.com/apex/ArticleAttachmentPortal?id=a1O0V0000090teVUAQ&pageName=ArticleContent

Figure 2:

Calculator Panel Indicating Signal Types to Access ("vt" information shown as mouse hovers over "vt' radio button)