[SI-LIST] Re: Article discussion on bad packages

Chris

Both of the points that you make are dead on.  I especially like your 
following comment:

>having program folks understand this type of issue allows us to better 
>quantify risk to
>programs when choosing a vendor if they better understand the shades of
>grey.  For instance, if vendor A can better describe their SI design and
>testing for a chip and produce good PCB design use guidelines when
>compared to vendor B, then vendor A is more desireable. 
>  
>
In a perfect engineering driven world, this is the optimal outcome.  
However, it is my experience that many chips, COTS, custom, FPGA and 
ASIC are chosen with overall cost as an overriding factor.  It is often 
hard to figure in the probablity of design failure, until it happens at 
least once. At that point it is often too late.  I've seen many choices 
for ASIC foundry made simply because of the design team's familiarity 
with one particular design flow.

Also, it is not necessarily true that Vendor A has a better chip, just 
because they have the information that you need.  Digging into many PCB 
design guides will often expose the man behind the curtain as being just 
a Carny, or expose the methodology as lacking.  However, having the 
information with which to make an informed engineering decision is 
always better than having no information at all.  Run like the wind from 
vendors who can supply no SI or power integrity (PI) information 
whatsoever, and have no clue what you're asking for.  Too many vendors 
see SI as being complete when they deliver a poorly constructed IBIS 
model to their customers.

Intel, Sun, Cisco, IBM and many others have excellent SI and PI design 
teams, because they have seen the failures and seen the light.


scott

-- 

Scott McMorrow
Teraspeed Consulting Group LLC
121 North River Drive
Narragansett, RI 02882
(401) 284-1827 Business
(401) 284-1840 Fax
(503) 750-6481 Cellular
http://www.teraspeed.com

Teraspeed is the registered service mark of 
Teraspeed Consulting Group LLC


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