Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Metal width consideration for SC circuit layout

Status
Not open for further replies.

rampat

Member level 4
Joined
Jun 27, 2007
Messages
69
Helped
3
Reputation
6
Reaction score
1
Trophy points
1,288
Location
bangalore
Activity points
1,756
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

Member level 5
Joined
Jan 22, 2008
Messages
89
Helped
9
Reputation
18
Reaction score
2
Trophy points
1,288
Location
Hyderabad
Activity points
1,853
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

Advanced Member level 5
Joined
Mar 4, 2008
Messages
7,229
Helped
2,117
Reputation
4,238
Reaction score
1,968
Trophy points
1,393
Location
USA
Activity points
57,967
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.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top