BD9873CP-V5 ROHM Electronics, BD9873CP-V5 Datasheet - Page 9

• Manufacturer Part Number: BD9873CP-V5
• Description: Simple Step-down Switching Regulators with Built-in Power Mosfet
• Manufacturer: ROHM Electronics

●Power Dissipation
●Tj (tip junction temperature) calculating method
© 2009 ROHM Co., Ltd. All rights reserved.
BD9873CP-V5,BD9874CP-V5
www.rohm.com
It is impossible to measure the tip junction temperature Tj outside the IC, but it can be calculated by the formula shown below.
Calculation method of tip junction temperature Tj
Calculation method of electric power W consumed by IC
15
10
5
0
0
(3) 11.0W
(2) 6.5W
(1) 2.0W
Tj=(W×θj－c)＋Tc
W=Vin×Iin－V
25
AMBIENT TEMPERATURE : Ta[C]
AMBIENT TEMPERATURE : Ta[℃]
50
OUT
×I
OUT
75
－V
Fig.28
θj－c
F
W
Tc
Vin
Iin
V
I
V
×I
OUT
OUT
F
OUT
100
×（1－V
9/12
：
：
：
： Input voltage
： Input voltage
： Output voltage
： Load Current
：
IC surface temperature (to be measured by thermocouple, etc.)
Power consumed by IC (calculated by the formula below)
Thermal resistance from the tip to the back of the package
125
12.5 ºC/W for TO220 package
Forward voltage of Schottky diode
OUT
/Vin）
150
(1) No heat sink
(2) Aluminum heat sink
(3) Aluminum heat sink
50×50×2（mm
100×100×2（mm
3
Technical Note
）
2009.07 - Rev.A
3
）