Revision 1/20/2009

Preliminary and all contents are subject to change without prior notice.

© Seaward Electronics, Inc., 2008. • www.seawardinc.com • Page 1

Features

Low Cost Emitter Drive PWM Solution

0.13W Standby Power

Current Mode Operation

Short Circuit Protection

Over-Current Protection

Over-Temperature Protection

Under-Voltage Lockout with Auto-restart

Available in TO-92 Packages

RoHS Compliant and 100% Lead (Pb)-Free

Description

The SE3900 is a green-mode Pulse Width Modulation

(PWM) controller. It is specifically designed for low

power applications such as 5W-20W Adaptors and

Off-line

battery

Chargers.

In

these

typical

applications, the low standby power, space saving,

and low cost are all required. SE3900 is a perfect

solution to meet these challenges. The typical

standby power is only 0.13Watt.

In normal operation, the SE3900 switches on and off

at a fixed switching frequency of about 60 kHz. With a

current limit capability of about 420mA, the SE3900

can directly drive the emitter of a high voltage NPN

transistor. When the output power falls below a given

level, the IC enters skip cycle mode to reduce power

consumption.

The SE3900 also features Under-Voltage Lockout ,

Over-Temperature

Protection,

Over-Current

and

Short Circuit Protections.

The SE3900 is available in TO-92 Packages.

Pin Configuration

Application

Battery Chargers

Universal Off-line Power Supplies

Power Adaptors

LED 3W-9W Low Cost Solutions with SE1051

Pin Description

Name

Pin#

Function

VCC

1

The power supply of the IC, and is generally connected to opto-coupler's emitter

GND

2

Supply ground

OUT

3

The output pin, connected to the emitter of NPN transistor