Thermal Relief Design

Chris_Heard@3com.com
Mon, 16 Jun 1997 10:50:36 -0400

I am designing a backplane that uses Positronics power connectors as its
interface to the the power supply. The pin in the backplane solders into a
0.070" diameter hole. Each pin can carry up to 15A and there are up to
five 2 oz. planes in the stackup that connect to the hole.

My dilemma is heat vs. dc resistance. I need to use a thermal relief on
all 5 planes that will allow me to heat the hole enough for solder to flow.
However, the thermal releif connection cannot be resistive enough to cause
a problem with IR drop.

The male/female mated total resistance is 1.7 milliohms.

Anybody have any experience with this problem?

Chris Heard
3Com Corporation
118 Turnpike Rd.
Southboro, M.A. 01772
508-490-5616