On 25 Sep 2006 16:27:30 -0700, "Telstar Electronics"
wrote in
. com:

Leland C. Scott wrote:
Exactly. That's why those diodes are place on the ceramic cap of the
device and not on the heat sink.

Having the sensing on top of the transistors is a poor location.


It's better than the heat sink.


The internal die is in intimate contact with the heat sink... not the
top!


Wrong. The ceramic package isn't hollow; on the contrary, it contacts
more of the junction's surface area than the heat sink flange (which,
BTW, doesn't make "intimate contact" with any part of the junction
because it is insulated from the die by the Be Oxide substrate). The
fact is that a transient pulse can heat and blow the junction before
it can dissipate into the -anything-, which it's more likely to happen
when the transistor is already hot from normal operation.


The heat sink... preferably near the device is the proper location

for any tracking device.


What part of "heat sink" don't you understand?