BD9122GUL_09 Datasheet, PDF (11/14 Pages) Rohm – Output 0.5A or Less High Efficiency Step-down Switching Regulator with Built-in Power MOSFET

BD9122GUL
Technical Note
●Cautions on PC Board layout
CO
①
VOUT
VCC
R2
②
CIN
L
SW
PVcc
Vcc
PGND
GND
EN
③
CITH
GND
RITH
EN
ADJ
ITH
R1
Fig.35 Layout diagram
① For the sections drawn with heavy line, use thick conductor pattern as short as possible.
② Lay out the input ceramic capacitor CIN closer to the pins PVCC and PGND, and the output capacitor Co closer to the pin PGND.
③ Lay out CITH and RITH between the pins ITH and GND as neat as possible with least necessary wiring.
●Recommended components Lists on above application
Symbol
Part
Value
Manufacturer
Series
L
Coil
2.2uH
FDK
MIPF2016D2R2
CIN Ceramic capacitor
10uF
murata
GRM188B30J106ME47B
CO Ceramic capacitor
10uF
murata
GRM188B30J106ME47B
VOUT=1.0V
VOUT=1.2V
2200pF
CITH Ceramic capacitor
VOUT=1.5V
murata
GRM15 Series
VOUT=1.8V
VOUT=2.0V
1000pF
VOUT=1.0V
VOUT=1.2V
6.8kΩ
MCR006 6801
RITH Resistance
VOUT=1.5V
ROHM
VOUT=1.8V
VOUT=2.0V
4.7kΩ
MCR006 4701
* 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 this IC 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
established between the SW and PGND pins.
●I/O equivalent circuit
・EN pin
・SW pin
PVCC PVCC
PVCC
EN
SW
・ITH pin
ITH
・ADJ pin
VCC
ADJ
www.rohm.com
© 2009 ROHM Co., Ltd. All rights reserved.
Fig.36 I/O equivalent circuit
11/13
2009.05 - Rev.A