Figure 11. Thermal resistance junction to ambient versus

copper surface under each lead (SMA Flat Notch)

0

50

100

150

200

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

R

(°C/W)

th(j-a)

S(Cu)(cm²)

Epoxy printed circuit board FR4, copper thickness: 35 µm

SMA Flat Notch

Figure 12. Thermal resistance versus lead length (DO-15)

R (°C/W)

th

0

20

40

60

80

100

120

5

10

15

20

25

Rth(j-a)

Rth(j-I)

L

(mm)

leads

STPS2150

Characteristics (curves)

DS3282 - Rev 8

page 5/13