BA30E00WHFP-TR(2009) Ver la hoja de datos (PDF) - ROHM Semiconductor
Número de pieza
componentes Descripción
Fabricante
BA30E00WHFP-TR
(Rev.:2009)
(Rev.:2009)
ROHM Semiconductor
BA30E00WHFP-TR Datasheet PDF : 10 Pages
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BA3259HFP,BA30E00WHFP
Technical Note
Function Explanation
1) Two-input power supply (BA30E00WHFP)
The input voltages (Vcc1 and Vcc2) supply power to two outputs (Vo1 and Vo2, respectively). The power dissipation
between the input and output pins can be suppressed for each output according to usage.
Efficiency comparison:
5V single input vs. 5V/3V two inputs
Regulator with single input and two outputs
Regulator with two inputs and two outputs
(Vo2=1.8V, Io1=Io2=0.3A)
Conventional
Vcc
5V
Vo1
REG1
Vo2
REG2
3.3 V/0.3 A
1.8 V/0.3 A
Power loss between input and output
(Vcc − Vo1) Io1 + (Vcc − Vo2) Io2
= (5 − 3.3) 0.3 + (5 − 1.8) 0.3
= 0.51W + 0.96W
= 1.47W
Single 5V input results in decreased
efficiency
Current
Vcc
5V
Vo1
REG1
3V
Vo2
REG2
3.3 V/0.3 A
1.8 V/0.3 A
Power loss between input and output
(Vcc1 − Vo1) Io1 + (Vcc2 − Vo2) Io2
= (5 − 3.3) 0.3 + (5 − 1.8) 0.3
= 0.51W + 0.36W
= 0.87W
Reduced power loss by
0.6W.
Additional 3V input improves efficiency
2) Standby function (BA30E00WHFP)
The standby function is operated through the EN pin. Output is turned on at 2.0 V or higher and turned off at 0.8 V or lower.
Thermal Design
If the IC is used under the conditions of excess of the power dissipation, the chip temperature will rise, which will have an
adverse effect on the electrical characteristics of the IC, such as a reduction in current capability. Furthermore, if the
temperature exceeds Tjmax, element deterioration or damage may occur. Implement proper thermal designs to ensure that
the power dissipation is within the permissible range in order to prevent instantaneous IC damage resulting from heat and
maintain the reliability of the IC for long-term operation. Refer to the power derating characteristics curves in Fig. 27.
Power Consumption Pc (W) Calculation Method:
BA3259HFP
Vcc
IP
Controller
Icc
GND
Vcc
Power
Tr
Vcc
Power
Tr
Power consumption of 3.3 V power
transistor
Pc1=(Vcc − 3.3) Io1
Power consumption of Vo2 power
3.3 V
Vo1 output
Io1
transistor
Pc2=(Vcc − Vo2) Io2
Power consumption by circuit current
Pc3=Vcc Icc
0.8 V to
3.3 V
Pc=Pc1 + Pc2 + Pc3
Vo2 output * Vcc: Applied voltage
Io2
Io1: Load current on Vo1 side
Io2: Load current on Vo2 side
Icc: Circuit current
BA30E00WHFP
Vcc1
IB1
Controller
Vcc2
IB2
Icc1+Icc2
GND
Vcc1
Power
Tr
Vcc2
Power
Tr
Power consumption of power transistor on
Vol1 (3.3 V output)
Pc1=(Vcc1 − Vo1) Io1
Power consumption of power transistor on
3.3 V
Io1 output
Io1
Vo2 (variable output )
Pc2=(Vcc2 − Vo2) Io2
Power consumption by circuit current
Pc3=Vcc1 Icc1 + Vcc2 Icc2
0.8 V to
3.3 V
Pc=Pc1 + Pc2 + Pc3
Io2 output * Vcc1, Vcc2: Applied voltage
Io2
Io1: Load current on 3.3 V output side
Io2: Load current on variable output side
Icc1, Icc2: Circuit currents
The Icc (circuit current) varies with the load.
Refer to the above and implement proper thermal designs so that the IC will not be used under conditions of
excess power dissipation Pd under all operating temperatures.
10
9
8 (3) 7.3W
7
Board size: 70 mm 70 mm 1.6 mm
(with a thermal via incorporated by the board)
Board surface area: 10.5 mm 10.5 mm
(1) 2-layer board (Backside copper foil area: 15 mm 15 mm)
(2) 2-layer board (Backside copper foil area: 70 mm 70 mm)
(3) 4-layer board (Backside copper foil area: 70 mm 70 mm)
10.0
5.0
2.0
1.0
6 (2) 5.5W
0.5
5
0.2
4
3 (1) 2.3W
2
1
0 0 25 50 75 100 125 150
0.1
0.05
0.02
0.01
0
AMBIENT TEMPERATURE: Ta [°C]
Fig. 27 Ambient Temperature vs. Power Dissipation
10.0
Unstable region
Stable region
5.0
2.0
1.0
00..75
0.2
0.1
0.05
0.02
Unstable region
Stable region
Unstable region
0.01
200 400 600 800 1000 0
Io [mA]
200 400 600 800 1000
Io [mA]
Fig.28 BA3259HFP ESR
Fig.29 BA30E00WHFP ESR
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© 2009 ROHM Co., Ltd. All rights reserved.
6/9
2009.04 - Rev.A
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