AL8805W5-7 Diodes Incorporated

NOT RECOMMENDED FOR NEW DESIGN USE AL8860 OR AL8861 AL8805 HIGH EFFICIENCY 36V 1A BUCK LED DRIVER Description Pin Assignments 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, (Top View) depending on the forward voltage of the LEDs, in series from a voltage source of 6V to 36V. Series connection of the LEDs provides 5 V SW 1 IN identical LED currents resulting in uniform brightness and eliminating the need for ballast resistors. The AL8805 switches at frequency up to GND 2 1MHz. This allows the use of small size external components, hence minimizing the PCB area needed. CTRL 4 SET 3 Maximum output current of AL8805 is set via an external resistor connected between the VIN and SET input pins. Dimming is achieved SOT25 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. Applications Features LED Driving Current up to 1A MR16 Lamps General Illumination Lamps 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) Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 2. See AL8805 Pin Descriptions Pin Number Pin Name Function 1 SW Switch Pin. Connect inductor/freewheeling diode here, minimizing track length at this pin to reduce EMI. 2 GND GND Pin Dimming and On/Off Control Input. Leave floating for normal operation. (V = V = 2.5V giving nominal average output current I = 0.1/R ) CTRL REF OUTnom S 3 CTRL Drive to voltage below 0.4V to turn off output current Drive with DC voltage (0.5V < V < 2.5V) to adjust output current from 20% to 100% of I CTRL OUTnom A PWM signal (low level 0.4V and high level > 2.6 transition times less than 1us) allows the output current to be adjusted below the level set by the resistor connected to SET input pin. 4 SET Set Nominal Output Current Pin. Configure the output current of the device. Input Supply Pin. Must be locally decoupled to GND with > 2.2F X7R ceramic capacitor see applications 5 V IN section for more information. Absolute Maximum Ratings ( T = +25C, unless otherwise specified.) A Symbol Parameter Ratings Unit ESD HBM Human Body Model ESD Protection 2.5 kV ESD MM Machine Model ESD Protection 200 V V Continuous V Pin Voltage Relative to GND -0.3 to 40 V IN IN V SET Pin Voltage Relative to V Pin -5 to +0.3 V SET IN V SW Voltage Relative to GND -0.3 to 40 V SW V CTRL Pin Input Voltage -0.3 to 6 V CTRL I DC or RMS Switch current 1.25 A SW-DC I Peak Switch Current (<10%) 2.5 A SW-PK T Junction Temperature 150 C J T Lead Temperature Soldering 300 C LEAD T Storage Temperature Range -65 to +150 C ST Caution: Stresses greater than the Absolute Maximum Ratings specified above, may cause permanent damage to the device. These are stress ratings only functional operation of the device at these or any other conditions exceeding those indicated in this specification is not implied. Device reliability may be affected by exposure to absolute maximum rating conditions for extended periods of time. Semiconductor devices are ESD sensitive and may be damaged by exposure to ESD events. Suitable ESD precautions should be taken when handling and transporting these devices Recommended Operating Conditions ( T = +25C, unless otherwise specified.) A Symbol Parameter Min Max Unit V Operating Input Voltage relative to GND 6.0 36 V IN V Voltage High for PWM Dimming Relative to GND 2.6 5.5 V CTRLH V Voltage Range for 20% to 100% DC Dimming Relative to GND 0.5 2.5 V CTRLDC V Voltage Low for PWM Dimming Relative to GND 0 0.4 V CTRLL I Continuous Switch Current 1 A SW T Junction Temperature Range -40 125 C J 2 of 17 March 2021 AL8805 Diodes Incorporated www.diodes.com Document number: DS43562 Rev. 5 - 3