[SI-LIST] Re: Layout service recommendations

Martin,

When outsourcing the design to a design house, be sure to find out what tool
they are using.

A big thing that makes the process work better is to take advantage of email
during the design process. Many PWB vendors have free viewers that work
pretty well for reviewing a layout in progress - even the same database can
be reviewed concurrently over the phone. The layout can be emailed and
reviewed on a regular basis to prevent cost/schedule delays.

On average, outsourcing works well, but I still prefer to use our in-house
layout design group. Design control is much more effective when you can draw
a picture on a whiteboard to explain what you want for specific layout
requirements. You also can keep them focused on your design and not
timeshare with another client's project. It's difficult to do that over the
phone.

Either way, you will still need to spend time with the layout designer to
get the layout correct. Effective Layout Designers have develop a
specialized discipline of viewing the design in a graphic sense like the
"flow" and "partitioning" of mixed signal boards. 

The trick for the Signal Integrity Engineer is to translate the schematic
and knowledge of the mixed signal design requirements into a graphical sense
that the Layout Designer understands. Working together with the Design
Engineer, the end result is a PWB that is what the Design Engineer
originally envisioned on time and within budget.

If you "throw it over the wall", it's okay, you will probably get another
opportunity to re-lay it out correctly after you spend hours, days, weeks
debugging Signal Integrity induced problems. You could have been debugging
code, testing and shipping the product (you know revenue producing things).
But then, there are alot of opportunities out there to find new employment
when you are actually made responsible for your decision. I hear Burger King
is accepting applications. 


Philip Ross Wellington
Mgr. Signal Integrity & EMI
L-3 Communications CSW


-----Original Message-----
From: Martin Euredjian [mailto:martin@xxxxxxxxxxxxxx]
Sent: Wednesday, July 31, 2002 3:57 PM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Layout service recommendations



Being almost ready to go to layout I've been thinking about the issues of
sending a design out to a service bureau instead of doing it in-house.
Unless you work for a large corporation (I don't) you might not have access
to the $100K+ EDA tools and support infrastructure (budget, bodies,
equipment, etc.) you might need to produce good designs that work "out of
the box".

My particular design is a small 5x7 in board that has a 1.5Gb/s front end
which gets deserialized and fed into FPGA's etc.  Most internal frequencies
are in the 100 to 200 MHz range, with wide busses.

Is it reasonable to assume that a good layout service can get this right the
first time?  What should one look for?  Are there any rules-of-thumb in
terms of cost?  What guarantees should one demand?  What should be the
hand-off process?  What's the best way to assure success?

Much like the list of recommended PCB houses, it might be nice to assemble a
list of high-speed-capable layout service houses.  I'll volunteer to compile
and post to this list.

Thank you,


===============================
 Martin Euredjian
  eCinema Systems, Inc.
       voice: 661-305-9320
       fax:   661-775-4876
  martin@xxxxxxxxxxxxxx
  www.ecinemasys.com
===============================



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