AL8841

Description

The AL8841 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 and 1.5A for MSOP-8EP package. Depending upon supply voltage and external components, this converter can provide up to 60W of output power.

The AL8841 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 CTRL pin. The CTRL 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 CTRL pin to Ground. Applying a voltage of 0.3V or lower to the CTRL pin will shut down the power switch.

The AL8841 is available in the thermally enhanced MSOP-8EP package and the small footprint TSOT25 package.

Feature(s)

• Wide Input Voltage Range: 5V to 40V
• Output Current up to 1A for TSOT25 and 1.5A for MSOP-8EP
• Internal 40V NDMOS Switch
• Typical 4% Output Current Accuracy
• Single Pin for On/Off and Brightness Control by DC Voltage or PWM Signal
• Recommended Analog Dimming Range: 10% to 100%
• Soft-Start
• High Efficiency (Up to 97%)
• Max 100% Switching Duty Cycle, Allows Bypass Mode, V_OUT equals to V_IN
• LED Short Protection
• Inherent Open-Circuit LED Protection
• Overtemperature Protection (OTP)
• Up to 1MHz Switching Frequency
• MSOP-8EP & TSOT25 Packages Available in Green Molding Compound (No Br, Sb)
• 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 (AL8841Q)

Application(s)

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