AL8807

HIGH EFFICIENCY LOW EMI 36V 1A BUCK LED DRIVER

AL8807

Document number: DS35281 Rev. 4 - 2

1 of 21

www.diodes.com

June 2012

© Diodes Incorporated

Description

The AL8807 is a step-down DC/DC converter designed to

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

to 9 LEDs, depending on the forward voltage of the LEDs, in

series from a voltage source of 6V to 36V. Series connection

of the LEDs provides identical LED currents resulting in

uniform brightness and eliminating the need for ballast

resistors. The AL8807 switches at frequency up to 1MHz with

controlled rise and fall times to reduce EMI. This allows the

use of small size external components, hence minimizing the

PCB area needed.

Maximum output current of AL8807 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.

Features

•

LED driving current up to 1.3A (MSOP-8EP)

•

Better than 5% accuracy

•

High efficiency up to 96%

•

Optimally controlled switching speeds

•

Operating input voltage from 6V to 36V

•

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)

•

MSOP-8EP Available in “Green” Molding Compound (No

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

Pin Assignments

Applications

•

MR16 lamps

•

General illumination lamps

•

12V powered LED Lamps

•

24V powered LED Lamps

Notes:

1. EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2). All applicable RoHS exemptions applied.Please visit our website at

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

Typical Application Circuit

SOT25

(Top View)

SW

GND

CTRL

SET

V

IN

(Top View)

MSOP-8EP

SET

GND

GND

CTRL

V

IN

N/C

SW

SW

 

100 nF

C1

1µF

C4

D1

DFLS 2100

D2

DFLS 2100

D3

DFLS 2100

D5

DFLS 2100

D4

DFLS 2100

GND

SW

GND

CTRL

U1

AL8807

0R15

R1

L1

33µH

100nF

C5

150µF

C2

150µF

C3

P1

P2

ANODE

CATHODE