© 2007 Fairchild Semiconductor Corporation

www.fairchildsemi.com

SG6859A • Rev. 1.0.3

4

Pin Configurations

Figure 4. SSOT-6 Pin Configuration

Figure 5. DIP-8 Pin Configuration

Pin Definitions

DIP

Pin #

SSOT

Pin #

Name

Description

1

6

GATE

The totem-pole output driver for driving the power MOSFET.

2

5

VDD

Power supply

3

NC

No connection

4

4

SENSE

Current sense. This pin senses the voltage across a resistor. When the voltage

reaches the internal threshold, PWM output is disabled. This activates over-current

protection. This pin also provides current amplitude information for current-mode

control.

5

3

RI

A resistor connected from the RI pin to ground generates a constant current source

used to charge an internal capacitor and determine the switching frequency.

Increasing the resistance reduces the amplitude of the current source and the

70kHz switching frequency.

6

NC

No connection

7

2

FB

Feedback. The FB pin provides the output voltage regulation signal. It provides

feedback to the internal PWM comparator, so that the PWM comparator can control

the duty cycle.

8

1

GND

Ground