AL8861
40V 1.5A BUCK LED DRIVER
Description
Pin Assignments
The AL8861 is a hysteresis mode DC-DC step-down converter,
designed for driving single or multiple series connected LEDs
efficiently from a voltage source higher than the LED voltage. The
device can operate from an input supply between 4.5V and 40V and
provide an externally adjustable output current up to 1A for TSOT25
package and 1.5A for SOT89-5 and MSOP-8EP packages. Depending
upon supply voltage and external components, this converter can
provide up to 40W of output power.
(Top View)
LX
GND
VSET
VIN
ISENSE
The AL8861 integrates the power switch and a high-side output
current sensing circuit, which uses an external resistor to set the
nominal average output current.
TSOT25
Dimming can be realized by applying an external control signal to the
VSET Pin. The VSET Pin will accept either a DC voltage signal or a
PWM signal.
(Top View)
LX
GND
VSET
VIN
1
2
3
5
4
The soft-start time can be adjusted by an external capacitor from the
VSET Pin to Ground. Applying a voltage of 0.2V or lower to the VSET
Pin can turn off the output and make the device enter into standby
state with low current consumption.
ISEN
SE
Features
Low BOM Counts
SOT89-5
Wide Input Voltage Range: 4.5V to 40V
Output Current up to 1.5A
ISENSE
VIN
Internal 40V NDMOS Switch
Typical 5% Output Current Accuracy
Single Pin for On/Off and Brightness Control by DC Voltage or
PWM Signal
LX
LX
Recommended Analog Dimming Range: 5% to 100%
Soft-Start
VSET
High Efficiency (Up to 97%)
MSOP-8EP
LED Short Protection
Inherent Open-Circuit LED Protection
RS Short Protection
Applications
Over Temperature Protection (OTP)
Up to 1MHz Switching Frequency
Pb-free TSOT25, SOT89-5 and MSOP-8EP Packages
Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
Halogen and Antimony Free. “Green” Device (Note 3)
LED Retrofit for Low Voltage Halogen
Low Voltage Industrial Lighting
LED Backlighting
Illuminated Signs
External Driver with Multiple Channels
Notes:
1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.
2. See http://www.diodes.com/quality/lead_free.html for more 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.
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www.diodes.com
October 2017
© Diodes Incorporated
AL8861
Document number: DS39435 Rev. 3 - 2