BD9151MUV Datasheet, PDF (13/17 Pages) Rohm – Output 1.5A or Less High Efficiency Step-down Switching Regulator with Built-in Power MOSFET

BD9151MUV
●BD9151MUV Caution of Board layout
Technical Note
RITH1
R1 _CITH1
U1
COUT3
L1
RESET ITH1 FB1 SW1 SW1
AGND
AVCC
PGATEB
PGND1
PVCC1
PVCC2
PGATE
PGND2
MONI
ITH2 FB2 EN
PGND2
SW2 SW2
COUT1
CIN1
CIN2
COUT2
RITH2
L2
VOUT3
CITH2
Fig.39 Example of board layout
VOUT1
VOUT2
①Lay out the input ceramic capacitor CIN closer to the pins PVCC and PGND, and the output capacitor Co closer to
the pin PGND.
②Lay out CITH and RITH between the pins ITH and GND as neat as possible with least necessary wiring.
※VQFN020V4040 (BD9151MUV) has thermal PAD on the reverse of the package.
The package thermal performance may be enhanced by bonding the PAD to GND plane which take a large area of PCB.
●Recommended parts list, using the application above
Symbol
L1,2
CIN1,CIN2
Cout1,Cout2
CITH1
RITH1
CITH2
RITH2
U1
Cout3
R1
Parts name
Inductor
Ceramic capacitor
Ceramic capacitor
Ceramic capacitor
Resistor
Ceramic capacitor
Resistor
Pch FET
Ceramic capacitor
Resistor
Value
2.2µH
22µF
22µF
330pF
22kΩ
220pF
15kΩ
-
22µF
10kΩ
Company
TDK
TAIYO YUDEN
Murata
Murata
Murata
Rohm
Murata
Rohm
Rohm
Murata
Rohm
Parts number
LTF5022-2R2N3R2
NR3012T2R2M
GRM32EB11A226KE20
GRM31CB30J226KE18
GRM18 Series
MCR03 Series
GRM18 Series
MCR03 Series
RT1A040ZP
GRM31CB30J226KE18
MCR03 Series
※The parts list presented above is an example of recommended parts. Although the parts are sound, actual circuit
characteristics should be checked on your application carefully before use. Be sure to allow sufficient margins to
accommodate variations between external devices and BU9151MUV when employing the depicted circuit with other
circuit constants modified. Both static and transient characteristics should be considered in establishing these margins.
When switching noise is substantial and may impact the system, a low pass filter should be inserted between the VCC and
PVCC pins, and a schottky barrier diode or snubber established between the SW and PGND pins.
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13/16
2009.08 - Rev.A