BD8151EFV, BD8157EFV
Technical Note
4/17
www.rohm.com
2009.07 - Rev.B
© 2009 ROHM Co., Ltd. All rights reserved.
●Reference Data (Unless otherwise specified, Ta = 25℃)
Fig. 7 FCLK Pin Current
Fig. 8 ENB Pin Current
Fig. 9 COMP Sinking vs Source
Current
0
5
10
15
20
0.0 0.5 1.0 1.5 2.0 2.5 3.0
ENB VOLTAGE : VENB[V]
ENB CURRENT : ENB[μA] .
-100
-50
0
50
100
1.0 1.1 1.2 1.3 1.4 1.5
COMP VOLTAGE : VCOMP[V]
COMP CURRENT : ICOMP[uA] .
-40℃
0
5
10
15
20
0.0 0.5 1.0 1.5 2.0 2.5 3.0
FCLK VOLTAGE : FCLK[V]
FCLK CURRENT : FCLK[μA] .
125
℃
25℃
-40℃
125℃
25℃
Fig. 5 Reference Voltage
Temperature
Fig. 6 Switching Frequency
Temperature
0
500
1000
1500
2000
-40 -15 10 35 60 85 110
AMBIENT TEMPERATURE : Ta[
℃
]
SWITCHING FREQUENCY : FSW[kHz]
Fig. 4 SS Source Current
-20
-16
-12
-8
-4
0
00.511.52
SS VOLTAGE : VSS[V]
SS CURRENT : ISS[μA]
2 .4
VFCLK=VCC
0.0
0.5
1.0
1.5
2.0
0 1.5 3 4.5 6 7.5
SUPPLY VOLTAGE : VCC[V]
REFERENCE VOLTAGE : VREF[V]
VFCLK=GND
Fig. 10 Max. Duty Ratio Temperature
Fig. 11 Vcc = 2.5 V Power
Efficiency
Fig. 12 Vcc = 3.3 V Power
Efficiency
50
60
70
80
90
100
0 0.05 0.1 0.15 0.2 0.25 0.3
OUTPUT CURRENT : IO[A]
EFFICIENCY [%]
50
60
70
80
90
100
0 0.15 0.3 0.45 0.6
OUTPUT CURRENT : IO[A]
EFFICIENCY [%]
0.02
VCC=3.3V f=600kHz
VCC=3.3V f=1200kHz
VCC=2.5V f=1200kHz
VCC=2.5V f=600kHz
80
85
90
95
100
-40 0 40 80 120
AMBIENT TEMPERATURE : Ta[
℃
]
Max Duty [%]
125
BD8157EFV
BD8151EFV
0.00
0.25
0.50
0.75
1.00
1.25
1.50
1.75
0123456
SUPPLY VOLTAGE : VCC[V]
SUPPLY CURRENT: ICC[mA] .
0.5
1.230
1.235
1.240
1.245
1.250
1.255
1.260
-40 -15 10 35 60 85 110
AMBIENT TEMPERATURE : Ta[
℃
]
REFERENCE VOLTAGE : VREF[V] .
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
01234
SUPPLY VOLTAGE : VCC[V]
STANDBY CURRENT : ICC[μA] .
Fig. 1 Total Supply Current
Fig. 3 Reference Voltage
Temperature
Fig. 2 Standby Current
25℃
150℃
125℃
25℃
-40℃
-40℃
