bd63847 ROHM Co. Ltd., bd63847 Datasheet - Page 16

• Manufacturer Part Number: bd63847
• Description: Micro Step 36v Stepper Motor Drivers
• Manufacturer: ROHM Co. Ltd.

●Thermal derating curve
© 2010 ROHM Co., Ltd. All rights reserved.
BD63847/63843EFV
www.rohm.com
HTSSOP-B28 has exposed metal on the back, and it is possible to dissipate heat from a through hole in the back. Also, the
back of board as well as the surfaces has large areas of copper foil heat dissipation patterns, greatly increasing power
dissipation. The back metal is shorted with the back side of the IC chip, being a GND potential, therefore there is a
possibility for malfunction if it is shorted with any potential other than GND, which should be avoided. Also, it is
recommended that the back metal is soldered onto the GND to short. Please note that it has been assumed that this
product will be used in the condition of this back metal performed heat dissipation treatment for increasing heat dissipation
efficiency.
5.0
4.0
3.0
2.0
1.0
0
4.70W
3.30W
1.85W
1.45W
25
4
3
2
1
50
Ambient temperature:Ta[C]
Fig.7 HTSSOP-B28 Thermal derating curve
75
85
100
16/19
Board③：2-layer board (Copper foil on the back 70mm*70mm)
Measurement machine：TH156（Kuwano Electric）
Measurement condition：ROHM board
Board size：70mm*70mm*1.6mm
(With through holes on the board)
The exposed metal of the backside is connected to the board with solder.
Board①：1-layer board (Copper foil on the back 0mm)
Board②：2-layer board (Copper foil on the back 15mm*15mm)
Board④：4-layer board (Copper foil on the back 70mm*70mm)
Board①：θ
Board②：θ
Board③：θ
Board④：θ
125
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ja
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=86.2°C W
=67.6°C W
=37.9°C W
=26.6°C W
150
Technical Note
2010.4 - Rev.A