Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic 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.

Register Log in

Analyzing a Circuit with "Worst Case" Method

Status
Not open for further replies.

Vauxdvihl

Member level 5
Joined
Dec 31, 1999
Messages
94
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
611
Hi friends,

i have to analyze my circuit with a "worst Case" Method.
This circuit contains a lot of resistor's, cap's and transtistors
(also CAN and LIN device.........because of Automotive) !

Can please somebody help me with giving me tips where to find stuff
about that and how to handle/calculate that.

All help is very welcome (like pdf's, I-Net Sides, files etc etc etc ).

Thank you very much for your help

Regards
 

toonafishy

Full Member level 6
Joined
Jun 18, 2002
Messages
369
Helped
38
Reputation
76
Reaction score
12
Trophy points
1,298
Location
Earth
Activity points
3,187
As a start, things like this:
Hot temperature, all component tolerances in one direction.
Hot Temperature, all component tolerances in the other direction.
Cold temp, etc.
Cold temp, etc.

Since you wan't worse case, you don't want to use Gaussian distribution on your tolerances.
 

Vauxdvihl

Member level 5
Joined
Dec 31, 1999
Messages
94
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
611
Thanks for your answer !

Maybe there is somebody who has some some papers for me ??
Papers (or I-NEt Sides, Doc's from Studys) who can explain me this method ???

Thank you very much

Regards
 

mild-seven

Junior Member level 2
Joined
Jan 19, 2003
Messages
22
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
164
Worst case design?

It means that all the tolerence of all components have to be calculated.
What papers would describe this ?
You have to examine and check all the circuit components and find
the datasheets. Then keyin all extreme-value of all components.

And re-examine the dsign results and see if design goal is met again.
 

okguy

Full Member level 6
Joined
Mar 1, 2002
Messages
360
Helped
15
Reputation
30
Reaction score
9
Trophy points
1,298
Location
China
Activity points
2,647
You should have the following worst cases :
- min temperature / min voltage supply / min process
- max temperature / min voltage supply / min process
- min temperature / max voltage supply / min process
- max temperature / max voltage supply / min process
- min temperature / min voltage supply / max process
- max temperature / min voltage supply / max process
- min temperature / max voltage supply / max process
- max temperature / max voltage supply / max process
But for analog CMOS processes you also have the case:
- NMOSmin/PMOSfast
- NMOSmax/PMOSmin
- Rmin/Rmax
- Cmin/Cmax

Well, if you use HSPICE or ELDO, use .alter command to run those cases, and .measure to simplify the analysis. The ELDO .defwave is also useful.

If your simulation is too long, try to gather the slow cases and the fast cases.

OkGuy?
 

Vauxdvihl

Member level 5
Joined
Dec 31, 1999
Messages
94
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
611
Thank you very much guys !!

@mild-seven
This papers descibes this !
http://www.designandevaluation.com/
WORST CASE CIRCUIT ANALYSIS HANDBOOKS
A TWO VOLUME SET OF WCCA HANDBOOKS

VOLUME 1 - An Introduction to Worst Case Circuit Analysis
VOLUME 2 - Worst Case Circuit Design and Analysis Guidelines

And i think there are a few more sources avaiable.....

Regards
 

okguy

Full Member level 6
Joined
Mar 1, 2002
Messages
360
Helped
15
Reputation
30
Reaction score
9
Trophy points
1,298
Location
China
Activity points
2,647
I cannot open that site.
Is there any mistake in your spelling ?

Okguy?
 

Vauxdvihl

Member level 5
Joined
Dec 31, 1999
Messages
94
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
611
@Okguy

I really do not know where the problem is ??? :p

It works very fine !

I've got another one for you...check this out (a really got example how describes the WCCA analyses....!!
http://www.devicelink.com/mem/archive/99/09/003.html

Maybe somebody knows other good sites (or Ebooks)

Regards
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top