Signals Integrity Analysis Checklist.

[BabaYaga]

Hi Guys,
I would like to have a discussion on SI analysis from beginner to advanced, so help me out guys.
The thing is i've got this freaky board that i'm designing, has got all sorts of interfaces, USB, DDR3, XAUI, 10GbE to name a few and i want to do its SI analysis on my own, I am a total amateur to this topic, and as always i don't have much time up my sleeve, so how about we share some info:-
I want to make a list of things to do for the SI analysis of a board:
Roughly speaking SI analysis is in 2 stages :- Post Layout, Pre Layout
Pre Layout:
i seriously don't know what people do here, never seen anyone implementing it, esp., in the contemporary times.
Post Layout:
Apparently checks like DDR3 simulations, Clocks, Buses, differentials, impedances etc., will be done.
So, as you can see i've got no knowledge of SI, so i would like to know how would an experienced guy would approach a sophisticated system with all such high speed interfaces, clearly outlined steps,I am not asking how to do, i am only asking what to do, i will figure out the implementation part on my own, lets have a discussion, u guys add points at the end i will make a comprehensive list, i'm doing this so that i will have a more focused learning in less amount of time, and moreover it will help a lot of amateurs like me.

Thanks & Regards
Bhavani T

 

[marce]

You really need SI software to do the checks, so what software are you going to use...
Then I read up all I could on SIV;
Howard Johnson
Eric Bogatin
Henry Ott
Ralph Morrison
Charles Pfeil

Firstly do you understand how signals travel round a board (TEM etc), and the effects of dielectrics on signal speed, also impedances.

 

[BabaYaga]

My client has Hyperlynx with him so i might end up using Hyperlynx, I am not sure about the software though(as my company might buy license for any other) and do understand basic jargon of SI and PI.
but still a pro SI engineer might have some basic SI simulations at the back of hand that he might perform every time he comes across a board.
I have Howard Johnson and Eric Bogatin, but those books are like humungous, i was looking for some simple signposts on which i can have a focussed research and study and may be i could go on a faster pace, not like the academic ones u've suggested, well as you know, in the industry time to market is what is important.

Regards

 

[marce]

I started by learning the basics of IBIS files and how to import them into the SIV software (this is one of the most critical skills required), the actual simulations I started on where DDR memory interfaces (1, 2 or 3) as there is so much data around regarding them that you can find guides on what to simulate.
Basically I will do a single shot step response to look at the waveform and what the PCB is doing to it.
Multiple cycles through single lines.
As above multiple lines.
As above with crosstalk.
Eye diagram simulations with varying amounts of jitter for the lines of interest.
I also built a library of stimulus's based on Engineers requirements and feedback, clock frequency's, different bit patterns etc.
Hope that gives a basic idea and helps.
As to learning it, I studied the more academic side along with using the actual software, so that I had a thorough understanding of what I was doing.

 

[BabaYaga]

Hi Marce,
Thanks for the info, now i might sound a little selfish or even foolish by asking u whether u can provide me with the library of stimulus that u have built i would definitely love to study them, u gave me IPC specs in one of my previous posts so it just persuaded me to ask (u see i don't want to give up without trying), its fine if u don't want to share, but it would be really helpful, Now which books do u mean by " I studied the more academic side", i feel SI/PI is a tough subject and books may not be sufficient, i might use some simulation software along with it, so any suggestions about the rough cases that i should simulate and check out as a thumb rule.

Regards