Technical Note
29/30
BD5446EFV
www.rohm.com
2010.05 - Rev.B
© 2010 ROHM Co., Ltd. All rights reserved.
●
Allowable Power Dissipation
Measuring instrument : TH-156(Shibukawa Kuwano Electrical Instruments Co., Ltd.)
Measuring conditions : Installation on ROHM’s board
Board size : 70mm×70mm×1.6mm(with thermal via on board)
Material : FR4
・
The board on exposed heat sink on the back of package are connected by soldering.
PCB
①
: 1-layer board(back copper foil size: 0mm×0mm),
θ
ja
＝
62.5
℃
/W
PCB
②
: 2-layer board(back copper foil size: 70mm×70mm),
θ
ja
＝
27.8
℃
/W
PCB
③
: 4-layer board(back copper foil size: 70mm×70mm),
θ
ja
＝
20.2
℃
/W
0
1
2
3
4
5
6
7
0
10 20
30
40 50
60
70 80
90 100 110 120 130 140 150
Ambient Temperature:Ta(
℃
)
Po
w
er
D
is
si
pat
ion P
d （
W
)
PCB
③
6.2W
PCB
②
4.5W
PCB
①
2.0W
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