AL8807 Datasheet, PDF (1/21 Pages) Diodes Incorporated – HIGH EFFICIENCY LOW EMI 36V 1A BUCK LED DRIVER

AL8807
HIGH EFFICIENCY LOW EMI 36V 1A BUCK LED DRIVER
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
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 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
(Top View)
SW
GND
CTRL
SOT25
(Top View)
SET
GND
GND
CTRL
MSOP-8EP
Applications
• MR16 lamps
• General illumination lamps
• 12V powered LED Lamps
• 24V powered LED Lamps
V_IN
SET
V_IN
N/C
SW
SW
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
D1
D3
DFLS 2100
P1
P2
D4
DFLS 2100 D2
C5 100nF
D5
C2
150µF
DFLS 2100 DFLS 2100
C3
150µF
DFLS 2100
R1
0 R15
U1
C1
CTRL
SW
100 nF
GND
AL8807
L1
33µH
ANODE
C4
1µF
CATHODE
GND
AL8807
Document number: DS35281 Rev. 4 - 2
1 of 21
www.diodes.com
June 2012
© Diodes Incorporated