AP8802 1A LED STEP-DOWN CONVERTER Description Pin Assignments The AP8802 is a step-down DC/DC converter designed to drive (Top View) (Top View) LEDs with a constant current. The device can drive up to thirteen LEDs, depending on the forward voltage of the LEDs, in series from SET 8 CTRL SET 8 CTRL a voltage source of 8V to 48V. Series connection of the LEDs GND 2 7 GND GND 2 7 GND AP8802 AP8802 provides identical LED currents resulting in uniform brightness and NC 3 6 SW NC 3 6 SW eliminating the need for ballast resistors. The AP8802 switches at 4 V 5 SW 4 V 5 SW IN IN frequencies up to 700kHz. This allows the use of small size SO-8 SO-8EP external components, hence minimizing the PCB area needed. (Top View) Maximum output current of AP8802 is set via an external resistor 1 10 connected between the V and SET input pins. Dimming is SET IN CTRL achieved by applying either a DC voltage or a PWM signal at the GND 2 9 GND AP8802 CTRL input pin. An input voltage of 0.2V or lower at CTRL shuts NC 3 8 NC down the output at SW and puts the device into a low-current NC 4 7 SW V standby state. 5 6 IN SW U-DFN3030-10 Features LED driving current up to 1A Applications High efficiency up to 92% Commercial & industrial lighting Operating input voltage up to 48V Small LCD panel backlight High switching frequency up to 700kHz Appliances interior lighting PWM/DC input for dimming control Architecture Detail lighting Built-in output open-circuit protection SO-8, SO-8EP and U-DFN3030-10 are 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) Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant. 2. See AP8802 1A LED STEP-DOWN CONVERTER Pin Descriptions Name SO-8 SO-8EP U-DFN3030-10 Function Switch Pin. Connect inductor/freewheeling diode here, minimizing track length at this pin SW 6, 5 6, 5 7, 6 to reduce EMI. GND 2 2 2, 9 GND pin SET 1 1 1 Set Nominal Output Current Pin. Configure the output current of the device. Dual function dimming control pin. Input voltage of 0.2V or lower forces the device into low current standby mode and shuts off the output. A PWM signal (driven by an open-drain/collector source) allows the output CTRL 8 8 10 current to be adjusted over a wide range up to 100%. An analog voltage between 0.3V and 2.5V adjusts the output current between 25% and 200% of the current set by 0.2V/R . S The input impedance is about 50k , and if the pin is left open V = V CTRL REF V 4 4 5 Input Supply Pin. Must be locally bypassed. IN NC 3 3 3, 4, 8 No connection Exposed pad: Internally connected to IC substrate. It should be connected to GND and as large as possible thermal mass for improved EP - EP EP thermal impedance and power dissipation capability. However the exposed pad is not a Power GND return path. The dedicated GND pins must be connected to 0V. See Land Pad diagrams. Functional Block Diagram Figure. 1 Functional Block Diagram 2 of 19 May 2012 AP8802 Diodes Incorporated www.diodes.com Document number: DS31766 Rev. 9 - 2