[PEDA] Thermal Impedance of Copper Areas

[Linden]

Greetings All,

Can anyone direct me to information on the relationship between copper
area and thermal impedance for SMD devices?

I have a D2PAK MOSFET that has a Thermal impedance of 40K/W junction to
ambient when mounted with a minimum of copper on the mounting tab..
I'd like to reduce this figure by adding a copper area (polygon or fill)
to the mounting tab.
The problem is I don't have a feel for how much copper is needed for a
particular reduction in thermal impedance.


Thanks in advance,

Linden Doyle