bd9845fv ROHM Co. Ltd., bd9845fv Datasheet - Page 13

• Manufacturer Part Number: bd9845fv
• Description: Single-output High Voltage High-frequency Step-down Switching Regulator Controller Type
• Manufacturer: ROHM Co. Ltd.

●I/O equivalent circuit diagram
When only one channel is used, process unused channels as shown above.
5) About board layout
(6) PIN processing of channel unused
CT
STB
In order to make full use of IC performance, fully investigate the items below in addition to general precautions.
・ Each output of OCP+/OCP- is such a sensitive circuit. When wiring is routed around, it is easily subjected to noise.
・ Switching of large current is likely to generate noise. Try to make the large current route (VIN, Rsense, FET, L, Di,
・ C
・ Also be careful not to allow common impedance to sense family GND.
VREF
VCC
4pin (STB)
VCC
Try to make the wiring as short as possible.
and Cout) as thick and short as possible, and try to apply one-point grounding for GND. OUT terminal is also a
switching line, and it must be wired along a distance as short as possible. (When multi-layer board is used, shielding
by intermediate layer also seems to be effective.)
protected against external influence.
INV
VREF
CT
12pin (INV)
VCC
5pin (C5V)
and C
2pin(CT)
VREF
VREF
VREF
VREF DT
1
VREF
VCC
VREF
VREF
14
are reference of all, and must be wired along the shortest distance to GND of IC stabilized to be
SS INV
13
VREF
VCC
VREF
12
C5V
Fig.43
FB
11
SEL
10pin (SEL)
OCP- OCP+ VCC OUT
VCC
9
VCC VCC
8
DT
7
6
VREF
6pin (OUT)
14pin (DT)
11pin (FB)
VREF
13/15
VCC
C5V
VCC
C5V
VREF
VREF
OUT
1pin (VREF)
FB
VCC
VCC
VREF
SS
VREF
OCP-
OCP+
3pin (GND) , 7pin (VCC)
8pin (OCP+)
9pin (OCP-)
13pin (SS)
VCC
C5V
VCC
C5V
GND
VCC
VREF
VREF
VCC
C5V
VCC
C5V
VCC