AL8805

HIGH EFFICIENCY 30V 1A BUCK LED DRIVER

AL8805

Document number: DS35030 Rev. 1 - 2

1 of 16

www.diodes.com

September 2010

© Diodes Incorporated

Description

The AL8805 is a step-down DC/DC converter designed to

drive LEDs with a constant current. The device can drive up

to 8 LEDs, depending on the forward voltage of the LEDs, in

series from a voltage source of 6V to 30V. Series connection

of the LEDs provides identical LED currents resulting in

uniform brightness and eliminating the need for ballast

resistors. The AL8805 switches at frequency up to 1MHz.

This allows the use of small size external components, hence

minimizing the PCB area needed.

Maximum output current of AL8805 is set via an external

Dimming is achieved by applying either a DC voltage or a

PWM signal at the CTRL input pin. An input voltage of 0.4V

or lower at CTRL switches off the output MOSFET simplifying

PWM dimming.

Pin Assignments

4SET

SW

1

CTRL

3

GND

2

(Top View)

SOT25

Features

•

LED driving current up to 1A

•

Better than 5% accuracy

•

High efficiency up to 98%

•

Operating input voltage from 6V to 30V

•

High switching frequency up to 1MHz

•

PWM/DC input for dimming control

•

Built-in output open-circuit protection

•

SOT25: Available in “Green” Molding Compound (No Br,

Sb) with lead Free Finish/ RoHS Compliant (Note 1)

Applications

•

MR16 lamps

•

General illumination lamps

Notes:

1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at

http://www.diodes.com/products/lead_free.html.

Typical Application Circuit