Jeff,

HOWZITGOIN?

Jeff Seeger wrote:

> 	I'm looking for empirical advice on thermal relief sizing.  The
> 	IPC 275 answer is a maximum copper attach of .160 or .080 (1 or 2
> 	oz cu), fine for loads but not sufficient for the supply side.
> 
> 	The application is a pressfit backplane with an intended (oof)
> 	fountain soldered power connector.  Problem with power connectors
> 	of late is that we're up to 10 amperes/pin, or to put it another
> 	way, ~twice the max recommended thermal connection.
> 
> 	On these particular backplanes there are also reflowed discrete
> 	components.  None of the manufacturers we're working with are
> 	using intrusive reflow yet.  (hint, hint?)
> 
> 	Is anyone having repeatable success using any other guideline?
> 	The IPC 275 answer does not mention specific soldering process
> 	but would presumably cover wave.  Will long-and-slow fountain 
> 	techniques suffice?  To make matters worse, not every pin on the
> 	connector has so much load (or copper).
> 

Typically, we put a thermal on the thru-hole pin and then we 
also run fat trace(s) to as many vias as required.  Each via 
is "flooded" to the plane (no thermal relief).

Thank you and have a FANTASTIC day!

Kevin L. Seaman (714) 221-4752

P.S. If your "reply" bounces back, then "send" to:
[log in to unmask]