Figure 11. Thermal resistance junction to ambient versus copper surface under tab (typical values, epoxy

printed board FR4, eCu = 35 µm) (PSMC (TO-277A))

0

20

40

60

80

100

120

0

1

2

3

4

5

6

7

8

9

10

SCu(cm²)

Rth(j-a) (°C/W)

PSMC (TO-277A)

STTH802SF

Characteristics (curves)

DS12649 - Rev 2

page 5/10