NOT RECOMMENDED FOR NEW DESIGN USE AL8860 or AL8861 (Both P/Ns Are Pin Compatible) AP8800A COST EFFECTIVE 28V BUCK 1W LED DRIVER Description Pin Assignments The AP8800A is a step-down DC/DC converter designed to drive (Top View) LEDs with a constant current. The device can drive up to 7 LEDs, depending on the forward voltage of the LEDs, in series from a 5 V SW 1 IN voltage source of 8V to 28V. Series connection of the LEDs provides identical LED currents resulting in uniform brightness and eliminating GND 2 the requirement for ballast resistors. The AP8800A switches at frequency up to 600kHz. This allows the use of small size external CTRL 4 SET 3 components, hence minimizing the needed PCB area. SOT25 Maximum output current of AP8800A is set via an external resistor 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 pin. An input voltage of 0.2V or lower at CTRL switches off the output MOSFET simplifying PWM dimming. Applications Features MR16 Lamps LED Driving Current up to 370mA General Illumination Lamps Better than 5% Accuracy High Efficiency up to 95% Operating Input Voltage from 8V to 28V Simple, Versatile Solution Requiring only 4 Components PWM/DC Input For Dimming Control Built-In Output Open-Circuit Protection TSOT25: 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) & 2015/863/EU (RoHS 3) compliant. 2. See NOT RECOMMENDED FOR NEW DESIGN USE AL8860 and AL8861 AP8800A (Both P/Ns Are Pin Compatible) Pin Descriptions Pin Name Pin Number Function SW 1 Switch Pin. Connect inductor/freewheeling diode here, minimizing track length at this pin to reduce EMI. GND 2 GND Pin Dimming and On/Off Control Input. Input voltage of 0.2V or lower forces the device into low current standby mode and shuts off the output. An open-drain/collector PWM signal allows the output current to be adjusted below the level set by the CTRL 3 resistor connected to SET input pin. The input impedance is about 50k, and if the pin is left open V = V . CTRL REF Drive with DC voltage (0.3V < V < 2.5V) to adjust output current from 24% to 200% of I CTRL OUTnom Set Nominal Output Current Pin. SET 4 Configures the output current of the device. Input Supply Pin. Must be locally decoupled to GND with > 2.2F X7R ceramic capacitor see applications V 5 IN section for more information. Functional Block Diagram Absolute Maximum Ratings ( T = +25C, unless otherwise specified.) A Symbol Parameter Ratings Unit V Continuous V Pin Voltage Relative to GND -0.3 to +30 V IN IN V Set Voltage Relative to V V -5 to V +0.3 V SET IN IN IN SW Voltage Relative to GND -0.3 to +30 V V SW CTRL Pin Input Voltage -0.3 to +5 V V CTRL Switch Current 0.45 A I SW Junction Temperature +105 C T J T Lead Temperature Soldering +300 C LEAD T Storage Temperature Range -55 to +150 C STG Caution: Stresses greater than the Absolute Maximum Ratings specified above, can 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 can be affected by exposure to absolute maximum rating conditions for extended periods of time. Semiconductor devices are ESD sensitive and can be damaged by exposure to ESD events. Suitable ESD precautions should be taken when handling and transporting these devices. 2 of 13 AP8800A March 2019 Diodes Incorporated www.diodes.com Document number: DS35100 Rev. 5 - 3