FC9911

2012. 10. 31

3/13

Revision No : 0

Pin Description

Pin #

Pin

Description

1

This pin is the input of a 250V high voltage regulator.

2

This is a power supply pin for all internal circuits. It must be bypassed with a low ESR capacitor to GND (at

least 0.1uF).

3

4

GND

Ground return for all circuits. This pin must be connected to the return path from the input.

5

CS

This pin is used to sense the drain current of the external power FET It includes a built-in 100ns (min)

blanking time.

6

SC

Slope compensation for current sense. A resistor between SC and GND will program the slope compensation.

In case of constant off-time mode of operation, slope compensation is unnecessary and the pin can be left

open.

7

This pin sets the frequency or the off-time of the power circuit. A resistor between RT and GND will program

the circuit in constant frequency mode. A resistor between RT and GATE will program the circuit in a constant

off-time mode.

8

the highest frequency oscillator.

9

This pin provides a programmable input current limit for the converter. The current limit can be set by using a

resistor divider from the REF pin. Soft start can also be provided using this pin.

10

REF

This pin provides 2% accurate reference voltage. It must be bypassed with at least a 10nF - 0.22µFcapacitor to

GND.

11

This pin is pulled to ground when there is an output short circuit condition or output over voltage condition.

This pin can be used to drive an external MOSFET in the case of boost converters to disconnect the load from

the source.

FAULT

12

OVP

This pin provides the over voltage protection for the converter. When the voltage at this pin exceeds 1.25V, the

gate output of the FC9911 is turned off and FAULT goes low. The IC will turn on when the power is

recycled.

13

level is applied to it, switching will resume.

14

GND.

15

The voltage at this pin sets the output current level. The current reference can be set using a resistor divider from

the REF pin.

16

Pin Configuration

16-Lead SOIC

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device.

These are stress ratings only, and functional operation of the device at these or any other conditions beyond those

indicated in the operational sections of the specifi cations is not implied. Exposure to absolute maximum rating conditions for extended

periods may affect device reliability.

Absolute Maximum Ratings

Parameter

Value

V

-0.5V to +250V

V

-0.3V to +13.5V

CS1, CS2 to GND

-0.3V to (V

PWMD to GND

-0.3V to (V

GATE to GND

-0.3V to (V

All other pins to GND

-0.3V to (V

(derate 10.0mW/°C above +25°C)

1000mW

Junction to ambient thermal impedance

Operating ambient temperature range

-40°C to +85°C

Junction temperature

+125°C

Storage temperature range

-65°C to +150°C

VIN

VDD

FDBK

FAULT

COMP

PWMD

IREF

REF

GND

CLIM

CS

GATE

OVP

SC

SYNC

RT

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

(top view)