Hi Joyce-
Basically, you have to model the bejeesus out of the arrangement. Nowadays
that modeling is CFD (Computational Fluid Dynamics). Big finite element
model. And you really need a physical model in addition to make sure all of
the fudge factors are properly calculated. Then, after you begin production,
you will find your customer changed something in the environment which
rendered most of the modeling moot! Getting good representations for actual
airflow in the application can be difficult to do also.
If you are longer on time and short on money, a bunch of physical models can
also get you there, but if you are going to be playing with the number of
copper planes in the pcb that can get expensive too. Used to be that
someone, like a university, would run a bunch of those kinds of modeling
tests and publish results so you could interpolate for your problem, but not
any more: the math models have taken over.
Wayne
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Yuan-chia Joyce Koo
Sent: Thursday, July 17, 2014 6:34 AM
To: [log in to unmask]
Subject: [TN] LIst of thermal conduction effective design
Gurus,
The most challenge in my short career of 24 years is application of thermal
components: the requirements just go up non stop. How do you handle the
thermal load in terms of static, dynamic or transient thermal load on high
density PWB/PWA, besides known build in heat sink. I am seeking for the low
provide conduction type, with limited or no convection cooling. Many
thanks.
(IBM's metal backing PWB is nice, but for multi-layer, >8 is a bit
difficult. Besides, double side or high density might have some limitation -
any new development in the field? ) Thanks in advance. (net a bit quiet, I
guess many on summer vacation mode with BBQ ;-).
joyce
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