SET V IN AL8807 HIGH EFFICIENCY LOW 36V 1A BUCK LED DRIVER Description Pin Assignments The AL8807 is a step-down DC/DC converter designed to drive LEDs (Top View) with a constant current. The device can drive up to 9 LEDs, depending on the forward voltage of the LEDs, in series from a SW V IN voltage source of 6V to 36V. Series connection of the LEDs provides identical LED currents resulting in uniform brightness and eliminating GND the need for ballast resistors. The AL8807 switches at frequency up to 1MHz with controlled rise and fall times to reduce EMI. This allows CTRL SET the use of small size external components, hence minimizing the PCB area needed. SOT25 Maximum output current of AL8807 is set via an external resistor (Top View) connected between the V and SET input pins. Dimming is achieved IN by applying either a DC voltage or a PWM signal at the CTRL input SET V IN pin. An input voltage of 0.4V or lower at CTRL switches off the output GND N/C MOSFET simplifying PWM dimming. GND SW SW CTRL Features LED Driving Current up to 1.3A (MSOP-8EP) MSOP-8EP Better Than 5% Accuracy High Efficiency up to 96% Applications Optimally Controlled Switching Speeds Operating Input Voltage from 6V to 36V MR16 Lamps PWM/DC Input for Dimming Control General Illumination Lamps Built-In Output Open-Circuit Protection 12V Powered LED Lamps SOT25, MSOP-8EP: Available in Green Molding Compound 24V Powered LED Lamps (No Br, Sb) 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 AL8807 Pin Descriptions Pin Number Pin Name Function SOT25 MSOP-8EP SW 1 5, 6 Switch Pin. Connect inductor/freewheeling diode here, minimizing track length at this pin to reduce EMI. GND 2 2, 3 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 CTRL 3 4 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. SET 4 1 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 8 V IN section for more information. Exposed pad/TAB connect to GND and thermal mass for enhanced thermal impedance. Should not be EP EP used as electrical ground conduction path. N/C 7 No Connection 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 -0.3 to +40 V V Continuous V Pin Voltage Relative to GND IN IN SW Voltage Relative to GND -0.3 to +40 V V SW CTRL Pin Input Voltage -0.3 to +6 V V CTRL SOT25 1.25 I DC or RMS Switch Current A SW-RMS MSOP-8EP 1.6 Peak Switch Current (<10%) 2.5 A I 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 f Maximum Switching Frequency 1 MHz SW SOT25 1 I Continuous Switch Current A SW MSOP-8EP 1.3 T Junction Temperature Range -40 +125 C J 2 of 20 March 2013 AL8807 Diodes Incorporated www.diodes.com Document number: DS35281 Rev. 5 - 2