Re: 1206 thermals

John Larkin wrote:

Measurements on a 1206 resistor (actually a platinum thinfilm RTD, to
be precise)

                   theta, K/W      thermal tau

in free air,         275              6 sec
#30 ww leads

on pcb, normal        69              1.5 s
kinda traces

on pcb, about         35              0.5 s
1" sq copper
island

Do these numbers seem reasonable? Anybody got data for other sizes?

John

I would expect that a 1206 would thermal very poorly. The aspect ratio sucks and so does the wing loading.

On the bright side, you won't need a dethermalizer.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
.