bd9842fv ROHM Co. Ltd., bd9842fv Datasheet - Page 13

• Manufacturer Part Number: bd9842fv
• Description: Dual-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.
STB
5) About board layout
(6) PIN processing of channel unused
CT
Pin 4, and 17 (INV1 and INV2)
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
VC C
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
Pin 15 (STB)
Pin 9 (C5V)
VCC
Pin 1 (CT)
and C
VREF
VREF
VREF
VREF
VREF DT
VCC
VREF
VREF
20
19
2
are reference of all, and must be wired along the shortest distance to GND of IC stabilized to be
VREF
SS INV
18
VCC
3
VREF
17
4
VREF
C5V
Fig.43
FB
16
5
OCP- OCP+VCC OUT
14
7
VCC VCC
13
8
Pin 10, and 11 (OUT1 and OUT2)
Pin 5, and 16 (FB1 and FB2)
12
Pin 2, and 19 (DT1 and DT2)
DT
11
10
Pin 20 (VREF)
VREF
VREF
13/15
VCC
VCC
C5V
VCC
VCC
C5V
VREF
VREF
VREF
OUT
FB
Pin 8, and 13 (OCP1+ and OCP2+)
Pin 7, and 14 (OCP1- and OCP2-)
Pin 6 (GND)
SS
Pin 3, and 18 (SS1 and SS2)
GND
VREF
OCP-
OCP+
VCC
C5V
VCC
C5V
Pin 12 (VCC)
VREF
VREF
VCC
C5V
VCC
C5V
VCC
VCC