[sdiy] thermal coupling question

[Magnus Danielson]

From: Michael Schulze <michael.schulze at oberlin.edu>
Subject: [sdiy] thermal coupling question
Date: Tue, 21 Jan 2003 15:05:33 -0500

> I have a question for the group on thermal coupling.
> 
> I am building a quad vco based on Jorgen Bergfor's design.  The expo
> converter (in my circuit) contains of a tempco resistor and a MAT-02
> transistor pair.  The MAT-02 is in a can enclosure - you know - like a TO-72
> but with 6 leads.  The pcb has a space for an 8 pin dip on which Jorgen
> assembled smt devices.  Not being an smt whiz I am just assembling my two
> huge crude components on an 8 pin dip header.
> 
> So my question is how to achieve the best thermal contact.  Do the two
> components need to be physically touching or can they just be next to each
> other with a dollop of some magical heat conducting compound binding them
> (...in the darkness...).  I'd hope to come up with something more elegant
> than heat sink grease...

The best thing you could do is to glue your tempco on the bottom side (yes,
between the legs) of the MAT-02. This way you will get the tightest possible
thermical "connection" between the actual MAT-02 die and tempco resistor.
Jörgen himself uses glue in the same fashion.

Cheers,
Magnus - who met Jörgen just last night...