Metal width consideration for SC circuit layout

[rampat]

Hi All,

In one of the switched cap circuit,I need to decide metal width for the signal paths depending on the current. i am not sure whether to consider peak current or average current for fixing the metal width.
I need to take take care of EM as well as IR considerations.
Attached image shows the simulated current profile in on the signal path.
Can some one tell me how to decide metal width w.r.t current waveform attached ?

Thanks
rampat

 

[varma_cs012]

Hi,

I am not a circuit expert. But as per the experience better to consider the peak current as definitely average current will be less that the peak current!

If you follow peak current, I don't think you will find EM violations neither IR drop issues! Please correct me if I am wrong.

Varma.

 

[dick_freebird]

Your waveform is periodic reversing so you should be able
to run at least 10X your foundry's DC electromigration
current density limit, absent an AC rule. You should try
getting a RMS current value of the waveform and check
that against an AC rule, as well as a time-averaged DC result
to check against their DC rules. Size the metal for the
more restrictive (fatter) of the two results.

 

[rampat]

thanks all for your replies