Data Sheet

FSFR1800 / FSFR1700-HS • Rev.1.0.1 3

FSFR-HS Series — Advanced Fairchild Power Switch (FPS™) for Half-Bridge Resonant Converter

Pin Configuration

Figure 3. Package Diagram

Pin Definitions

Pin # Name Description

1 DL This is the drain of the high-side MOSFET, typically connected to the input DC link voltage.

2 LS This is the line-sensing pin for the input voltage Under-Voltage Lockout (UVLO).

3 RT

This pin is used for controlling the switching frequency in normal operation. When any

protections are triggered, the internal Auto/Restart (A/R) circuit starts to sense the voltage on

the pin, which is discharged naturally by external resistance. The IC can be operated with

A/R when the voltage decreases 0.1 V. Typically, an opto-coupler is connected to control the

switching frequency for the output voltage regulation and resistors for setting minimum /

maximum operating frequency.

4 CS

This pin senses the current flowing through the low-side MOSFET. Typically, negative

voltage is applied to this pin.

5 SG This pin is the ground of the control part.

6 PG This pin is the power ground. This pin is connected to the source of the low-side MOSFET.

7 LV

This pin is the supply voltage of the control IC.

8 NC No connection

9 HV

This is the supply voltage of the high-side gate-drive circuit.

10 CTR This is the drain of the low-side MOSFET. Typically, a transformer is connected to this pin.