BD9775FV-E2 Rohm Semiconductor, BD9775FV-E2 Datasheet - Page 7

• Manufacturer Part Number: BD9775FV-E2
• Description: IC REG SW STEP DOWN HE 28-SSOP
• Manufacturer: Rohm Semiconductor
• Type: Step-Down (Buck)r

Specifications of BD9775FV-E2

• Internal Switch(s): No
• Synchronous Rectifier: Yes
• Number Of Outputs: 2
• Current - Output: 400mA
• Frequency - Switching: 100kHz
• Voltage - Input: 6 ~ 30 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-SSOP
• Power - Output: 640mW
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: BD9775FV-E2TR

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BD9775FV
www.rohm.com
2) Oscillator Synchronization by External Pulse Signal
3) Setting the Over Current Threshold Level
At the operation the oscillator is externally synchronized, input the synchronization signal into Fin in addition to connect a
resistor and a capacitor at RT and CT, respectively. Input the external clock pulse on Fin, which is higher frequency than
the fixed one. However, the frequency variation should be less than 20%. Also, the duty cycle of the pulse should be set
from 10% to 90%.
Short Fin to GND if the function of external synchronization is not needed.
The OCP detection level (Iocp) is determined by the ON resistance (R
(Rcl) which is placed between CL and VCC.
To prevent a malfunction caused by noise, place a capacitor (Ccl) parallel to Rcl.
If OCP function is not needed, short VS to VCC, and short CL to GND.
Iocp =
CT
Fin
With OCP
VS
CL
Rcl
R
ON
Fig.4 CT Waveform during Synchronized with External Pulse
×10
To Main MOSFET Drain
Rcl
Ccl
-5
Fig.5 Without Synchronization Signal
[A] (typ.)
Fig.6 CL, VS Pin Connection
Fin
VCC
7/14
Without OCP
ON
) of the main MOSFET switch and the resistance
VS
CL
： Fixed with RT and CT
： Synchronized
VCC
Technical Note
2011.05 - Rev.A