© 2007 Fairchild Semiconductor Corporation

www.fairchildsemi.com

FSQ0565R, FSQ0765R Rev. 1.0.0

4

Pin Configuration

Figure 3. Pin Configuration (Top View)

Pin Definitions

Pin #

Name

Description

1Drain

SenseFET drain. High-voltage power SenseFET drain connection.

2GND

Ground. This pin is the control ground and the SenseFET source.

Power Supply. This pin is the positive supply input. This pin provides internal operating cur-

rent for both start-up and steady-state operation.

4FB

Feedback. This pin is internally connected to the inverting input of the PWM comparator. The

collector of an opto-coupler is typically tied to this pin. For stable operation, a capacitor should

be placed between this pin and GND. If the voltage of this pin reaches 6V, the overload pro-

tection triggers, which shuts down the FPS.

5

Sync

Sync. This pin is internally connected to the sync-detect comparator for quasi-resonant switch-

ing. In normal quasi-resonant operation, the threshold of the sync comparator is 1.2V/1.0V.

Start-up. This pin is connected directly, or through a resistor, to the high-voltage DC link. At

start-up, the internal high-voltage current source supplies internal bias and charges the exter-

6. V

str

5. Sync

4. FB

3. V

CC

2. GND

1. Drain

FSQ0765R Rev.00