BD9850FVM-TR Rohm Semiconductor, BD9850FVM-TR Datasheet - Page 11

• Manufacturer Part Number: BD9850FVM-TR
• Description: IC REG SW STEP DOWN HI EFF 8MSOP
• Manufacturer: Rohm Semiconductor
• Type: Step-Down (Buck)r
• Series: -r

Specifications of BD9850FVM-TR

• Internal Switch(s): No
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Current - Output: 200mA
• Frequency - Switching: 100kHz ~ 2MHz
• Voltage - Input: 4 ~ 9 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• Power - Output: 587mW
• Mounting Style: SMD/SMT
• Pwm Type: Controller
• Frequency - Max: 2MHz
• Duty Cycle: -
• Voltage - Supply: 4 V ~ 9 V
• Buck: Yes
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

• Setting of oscillation frequency (BD9851EFV)
• Setting of timer of short circuit protection circuit (BD9851EFV)
Connecting a resistor to the RT pin (pin 2) and a capacitor to the CT pin allows
for the setting of oscillation frequency.
In order to use one channel, treat the pins of unused channel as shown above.
• Setting of maximum duty (BD9851EFV)
• Pin treatment of unused channels (BD9851EFV)
Fig. 22 Pin treatment procedure for unused channel on BD9851EFV
T
DUTY(max.) = 100 × (V
V
SCP
DTC
1000
1000
DUTY(max.)
V
Vth0
Vth100
100
O
DTC
10
T
= 7.45 × 10
= 2.5 × R2 / (R1 + R2)
SCP
SCP
1
Fig. 20 RT vs. Oscillation frequency
:
:
Time from output short circuit to latch stop [sec]
Capacitance of capacitor between the SCP and
GND pins [F]
Upper : Pin No. to be treated when the CH1 is not used
Lower : Pin No. to be treated when the CH2 is not used
SEL1
(18)
Vcc
(1)
C
C
CT
C
CT
=1200pF
CT
=220pF
5
NON2
=33pF
× C
: Maximum duty [%]
: DTC pin voltage [V]
: 0% duty threshold voltage [V]
: 100% duty threshold voltage [V]
(4)
Timing Resistance (kΩ)
SCP
Setting procedure
Setting procedure
V
(17)
(16)
INV
(5)
REF
DTC
– Vth0) / (Vth100 – Vth0)
10
(15)
FB
(6)
DTC
(13)
(7)
PVcc
(18)
(12)
Vcc
(8)
OUT
(11)
(9)
100
11/16 5
Fig. 19 Setting procedure for BD9851EFV oscillation frequency
1000
1000
100
C
10
SCP
10
R1
R2
Fig. 20 CT vs. Oscillation frequency
Application
Application
Timing Capacitance(pF)
V
SCP (14)
10
DTC (13)(7)
REF
R
C
RT
CT
(17)
100
R
R
RT
RT
RT (2)
CT (3)
=4.7kΩ
=24kΩ
1000