BD9775FV-E2 Rohm Semiconductor, BD9775FV-E2 Datasheet - Page 23

• 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

2) Oscillator Synchronization by External Pulse Signal
3)Setting the Over Current Threshold Level
The OCP detection level（Iocp）is determined by the ON resistance (R
(Rcl) which is placed between CL and VCC.
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%.
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.
Short Fin to GND if the function of external synchronization is not needed.
CT
Fin
With OCP
Iocp ＝
VS
CL
Rcl
R
ON
Without Synchronization Signal
CT Waveform during Synchronized with External Pulse
To Main MOSFET Drain
CL, VS Pin Connection
Rcl
Ccl
×10
Fin
-5
[A] （typ.）
VCC
23/29
Without OCP
ON
) of the main MOSFET switch and the resistance
VS
CL
： Fixed with RT and CT
： Synchronized
VCC