AL8861

Description

The DIODES^TM 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.

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.

Dimming can be realized by applying an external control signal to the V_SET pin. The V_SET pin will accept either a DC voltage signal or a PWM signal.

The soft-start time can be adjusted by an external capacitor from the V_SET pin to Ground. Applying a voltage of 0.2V or lower to the V_SET pin can turn off the output and make the device enter into standby state with low current consumption.

Feature(s)

• Low BOM Counts
• Wide Input Voltage Range: 5V to 40V
• Output Current up to 1.5A
• Internal 40V NDMOS Switch
• Typical 5% Output Current Accuracy
• Single Pin for On/Off and Brightness Control by DC Voltage or PWM Signal
• Recommended Analog Dimming Range: 5% to 100%
• Soft-Start
• High Efficiency (Up to 97%)
• LED Short Protection
• Inherent Open-Circuit LED Protection
• R_S Short Protection
• Overtemperature 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)
• An Automotive-Compliant Part is Available Under Separate Datasheet (AL8861Q)

Application(s)

• LED retrofit for low voltage halogen
• Low voltage industrial lighting
• LED backlighting
• Illuminated signs
• External driver with multiple channels