Diodes AL8805 User Manual
Al8805, Description, Features
AL8805
Document number: DS35030 Rev. 4 - 2
1 of 16
July 2012
© Diodes Incorporated
AL8805
HIGH EFFICIENCY 36V 1A BUCK LED DRIVER
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 36V. 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 resistor
connected between the V
IN
and SET input pins. 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 1A
•
Better than 5% Accuracy
•
High Efficiency up to 98%
•
Operating Input Voltage from 6V to 36V
•
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
Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
Halogen and Antimony Free. “Green” Device (Note 3)
Pin Assignments
4
SET
5
V
IN
SW
1
CTRL
3
GND
2
(Top View)
SOT25
Applications
• MR16
Lamps
•
General Illumination Lamps
Notes:
1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.
2. Se information about Diodes Incorporated’s definitions of Halogen- and Antimony-free, "Green" and Lead-free.
3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and
<1000ppm antimony compounds.
Typical Applications Circuit