Through body thermal resistance of SOT223?

[cupoftea]

Hi,
We have 0.85W in a SOT223. It only has a small bit of thermal copper pour within the footprint boundary, between middle pin and tab pin.
So we need to gap pad it to metal enclosure with 2.5mm thick gap pad.....but do you know the RTHjc going through the plastic body?


The following doesnt tell us the "thru' body" RTHja.

Infineon, Resistance - Theory and Practice

S p e c i a l S u b j e c t B o o k J a n u a r y 2 0 0 0 S M D P a c k a g e s N e v e r s t o p t h i n k i n g T h e r m a l R e s i s t a n c e T h e o r y a n d P r a c t i c e h t t p : / / w w w. i n f i n e o n. c o m

www.academia.edu

--- Updated Aug 28, 2023 ---

i Seem to remember 30degc/w for QFN FETs..(through the plastic body)...so for SOT223, you would say some 45c/w?

 

[cupoftea]

The following...
SOT223 RthJA
....on page 6..appears to show that with our ~9mm^2 of thermal copper under the SOT223, we will get a RthJA of some 135degC/W.
(This refers to 2oZ copper)
Would you agree with this?

--- Updated Aug 28, 2023 ---

I had a post on EDAboard on through-plastic-body thermal resistance of SMD FETs in approx 2016....but cant seem to find it now. That would be of relevance here.

--- Updated Aug 28, 2023 ---

Approx April to November 2016