Latch timing analysis

[deepa1206]

Hi , can anyone please help me answer the question regarding latch timing analysis? I have attached the file.

 

[jbeniston]

You want us to do your homework?

 

[deepa1206]

No, I am not a student looking for help with homework..

I am preparing for job interviews and as I was searching websites for interview questions, I came across a question paper from MIT.. One of the questions is the attached file.. Just brushing up my basics..

If you can help, please do..

 

[jbeniston]

If I give you the answers, will you give me the job?

How about you tell us your answers, then we'll tell you if you are correct or not?

 

[deepa1206]

These are my answers for the first part :


(A)

D-latch:
TCQMIN = _5______
TCQMAX = __5_____
TDQMIN = __12_____
TDQMAX = __12_____
CL1: TPDMIN = ___8____ TPDMAX = ___32____
CL2: TPDMIN = ___10____ TPDMAX = ___38____

Are they right?

 

[rakko]

D-latch:
TCQMIN = _5______
TCQMAX = __20_____
TDQMIN = __12_____
TDQMAX = __?_____
CL1: TPDMIN = ___32____ TPDMAX = ___?____
CL2: TPDMIN = ___38____ TPDMAX = ___?____

I don't think you can measure from unknown to unknown and report a mix/max timing. What the shaded area means is that either one of the signals can be high or low during this time. In other words these shaded timing areas are variables. Only the timings from known to known values are for certain.