[SOLVED] What does the "minimum recommended pad" mean for thermal resistance?

[ridgemao1983]

www.onsemi.com/pub/Collateral/MBRB1045-D.PDF

The datasheet says:
Thermal Resistance Junction −to −Ambient (Note 2) is 68C/W
When mounted using minimum recommended pad size on FR −4 board.
The package is DPAK CASE 369C−01.


What does the "minimum recommended pad" mean? Does it mean I don't need to place thermal vias under the DPAK pad, so I can place other compoments just under the DPAK footpring on the other side of the PCB? And at this time, the thermal resistance is still 68C/W ?

thanks.

 

[mtwieg]

That means you'll get that thermal performance if you just use the PCB footprint given in the datasheet. If you use a larger copper pour for the cathode tab, along with thermal vias to a pour on the opposite side, you'll get lower Rja.