ba00dd0wcp-v5 ROHM Co. Ltd., ba00dd0wcp-v5 Datasheet - Page 6

• Manufacturer Part Number: ba00dd0wcp-v5
• Description: 2a Low Dropout Voltage Regulator With Shut Down Switch
• Manufacturer: ROHM Co. Ltd.

BA00DD0WCP-V5,BA00DD0WHFP,BA00DD0WT,
BA00CC0WT,BA00CC0WT-V5,BA00CC0WCP-V5,BA00CC0WFP
●Thermal Design
●Terminal Vicinity Settings and Cautions
© 2009 ROHM Co., Ltd. All rights reserved.
www.rohm.com
10
9
8
7
6
5
4
3
2
1
0
0
HRP-5
When using at temperatures over Ta=25℃, please refer to the heat reducing characteristics shown in Fig.30 through 32.
The IC characteristics are closely related to the temperature at which the IC is used, so it is necessary to operate the IC at
temperatures less than the maximum junction temperature Tj
Fig.31 shows the acceptable loss and heat reducing characteristics of the TO220FP package The portion shown by the
diagonal line is the acceptable loss range that can be used with the IC alone. Even when the ambient temperature Ta is a
normal temperature (25℃), the chip (junction) temperature Tj may be quite high so please operate the IC at temperatures
less than the acceptable loss Pd.
The calculation method for power consumption Pc(W) is as follows :
Solving this for load current IO in order to operate within the acceptable loss,
It is then possible to find the maximum load current Io
Calculation Example
Example 1) When Ta=85℃, Vcc=8.3V, Vo=3.3V, BA33DD0WT
Please refer to the above information and keep thermal designs within the scope of acceptable loss for all operating
temperature ranges. The power consumption Pc of the IC when there is a short circuit (short between Vo and GND) is :
・Vcc Terminal
・CTL Terminal
③ 7.3W
② 5.5W
① 2.3W
Please attach a capacitor (greater than 0.33μF) between the Vcc and GND.
The capacitance values differ depending on the application, so please chose a capacitor with sufficient margin and verify
the operation on an actual board.
The CTL terminal is turned ON at 2.0V and higher and OFF at 0.8V and lower within the operating power supply voltage range.
The power supply and the CTL terminal may be started up and shut down in any order without problems.
Board size : 70×70×1.6 ㎜
Board front copper foil area : 10.5×10.5 ㎜
①2-layer board (back surface copper foil area :15×15 ㎜
②2-layer board (back surface copper foil area :70×70 ㎜
③4-layer board (back surface copper foil area :70×70 ㎜
Pc = (Vcc-Vo)×Io＋Vcc×Icca
Acceptable loss Pd≦Pc
25
Io≦
Io≦
Io≦200mA (Icca : 2mA)
Pc=Vcc×(Icca＋Ishort)
Ambient temperature:Ta(℃）
Pd – Vcc×Icca
1.04－8.3×Icca
50
Vcc－Vo
Fig.30
75
3
（board contains a thermal）
5
100
2
125
（Please refer to Figs.8 and 20 for Icca.）
2
2
2
)
)
)
150
With the IC alone : θja=62.5℃/W → -16mW/℃
25℃=2000mW → 85℃=1040mW
25
20
15
10
5
0
（ 1 ） 20.0
（ 2 ） 2.0
0
To225FP-5
（1）
（2）
25
When using a maximum heat sick : θj-c=6.25(℃/W)
When using an IC alone : θj-c=62.5(℃/W)
MAX
Ambient temperature:Ta(℃）
50
with respect to the applied voltage Vcc at the time of thermal design.
6/9
Fig.31
MAX
Ishort : Short circuit current
75
.
100
125
150
Icca：
Vcc：
2.0
1.6
1.2
0.8
0.4
0.0
Vo：
Io：
TO252-5
0
1.30
Input voltage
Output voltage
Load current
Circuit current
Mounted on a Rohm standard board
Board size : 70×70×1.6 ㎜
Copper foil area :7×7 ㎜
TO252-5θja=96.2(℃/W)
25
Ambient temperature:Ta(℃）
50
Technical Note
2009.04 - Rev.A
Fig.32
75
100
125
150