BD9845FV Datasheet, PDF (6/16 Pages) Rohm – Single/Dual-output High-frequency Step-down Switching Regulator(Controller type)

BD9845FV
Technical Note
●Block diagram/Pin layout
VREF
DT
FB
SS
INV
CT
VCC
STB
VCC
SEL
OCP+ OCP-
VREF
REG
STB
(2.5V)
VREF
2μA
SSOFF
1V±10mV
+
+ ERR
-
+
MASTER
-
/SLAVE
DTOFF
-
DT
+
1.25V
DTLow
+
+ PWM
-
VCC
OCP
+
OCP
-
50mV±10mV
C5V
VCC
REG
C5V (VCC-5V)
VCC
LS
DRV
C5V
200μA
+
--
200μA
OSC
2.0V
1.5V
PROTECTION LOGIC
OCP
Hold time
(1.6msec)
DTLow
SSOFF
DTOFF
TSD
TSD
MASTER
/SLAVE
UVLO
TSD
2V
1.5V
Hold time
(0.2msec)
VCC
VREF
C5V
3.2V
2.2V
UVLO
UVLO
3V
C5V
OUT
VREF
CT
GND
STB
C5V
OUT
VCC
DT
SS
INV
FB
SEL
OCP-
OCP+
Fig.29 Pin layout
Fig.28 Block diagram
GND
Terminal Terminal
number name
Function
1
VREF Reference voltage (2.5V) output terminal
2
CT
Timing capacity external terminal
3
GND GROUND
4
STB Standby mode setting terminal
5
C5V
Output L side voltage (Vcc-5V)
6
OUT Output
7
Vcc Power terminal
8
OCP＋ Output Overcurrent detector + Input terminal
9
OCP－ Output Overcurrent detector - Input terminal
10
SEL
Master/Slave mode setting terminal
11
FB
Output Error amplifier output terminal
12
INV Output Error amplifier - input terminal
13
SS
Output Soft start time setting terminal
14
DT
Output Dead time setting terminal
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2009.05 - Rev.A