AL3159FSG-7 Diodes Incorporated

AL3159 HIGH EFFICIENCY 1x/2x CHARGE PUMP FOR WHITE LED APPLICATIONS Description Pin Assignments The AL3159 is a low noise, constant frequency charge pump DC/DC converter that uses a Dual mode load switch (1x), and (2x) conversion for white LED applications. The AL3159 is capable of driving nine LED channels at 20mA from a 2.7V to 5.5V input. The current sinks may be operated using three simple logic control inputs individually or in parallel for driving higher-current LEDs. Low external part counts (one 1F flying capacitor and two 2.2F capacitors at V and V ) make this part ideally suited for IN OUT small, battery-powered applications. AL3159 digital inputs are used to enable or disable the LED channels with a fixed default current settings at 20mA or other factory programming options available. Each output of the AL3159 is equipped with built-in protection for V short circuit and auto-disable for LED short conditions. Built-in OUT soft-start circuitry prevents excessive inrush current during start-up and mode switching. A low-current shutdown feature disconnects the load from V to reduce quiescent current less than 1A. IN The AL3159 is available in a lead-free, space-saving, thermally enhanced 20-pin 3 x 3mm QFN package. Applications Features Mobile Phone White LED Backlighting and Indicators V range: 2.7V to 5.5V IN PDA White LED backlighting Up to 93% Max Power Efficiency Battery-operated Phone Main and Sub Screen White LED 1% Current Matching Accuracy Between Channels Backlighting Drives up to 9 configurable Channels of LEDs Three simple logic decoding LED On/Off control inputs Low transition threshold voltage typical 150 mV Dual-Mode 1x and 2x Charge Pump 1.2 MHz Constant Switching Frequency V short circuit and Thermal Protections OUT Soft Start for reducing inrush current I <1A in Shutdown Q Thermally-Enhanced QFN3030-20 Package: Available in Green Molding Compound (No Br, Sb) Lead Free Finish/ RoHS Compliant (Note 1) Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at AL3159 HIGH EFFICIENCY 1x/2x CHARGE PUMP FOR WHITE LED APPLICATIONS Pin Descriptions Pin Name Pin Number Description D8 1 Current sink input 8. Connected to V when un-used. OUT D9 2 Current sink input 9. Connected to V when un-used. OUT CTL1 3 Control Pin 1 CTL3 4 Control Pin 3 CTL2 5 Control Pin 2 PGND 6 Charge Pump Switch Ground CN 7 Negative Terminal of Flying Capacitor V 8 Input Power Supply. Requires 2.2F capacitor between this pin and ground. IN CP 9 Positive Terminal of Flying Capacitor NC 10,19 No-Connect Charge pump output to drive load circuit. Requires 2.2F capacitor between this pin V 11 OUT and ground. D1 12 Current sink input 1. Connected to V when un-used. OUT D2 13 Current sink input 2. Connected to V when un-used. OUT D3 14 Current sink input 3. Connected to V when un-used. OUT D4 15 Current sink input 4. Connected to V when un-used. OUT D5 16 Current sink input 5. Connected to V when un-used. OUT GND 17 Ground D6 18 Current sink input 6. Connected to V when un-used. OUT D7 20 Current sink input 7. Connected to V when un-used. OUT GND EP PAD Exposed Pad (bottom). Connected to GND directly underneath the package. Functional Block Diagram 2 of 10 January 2011 AL3159 Diodes Incorporated www.diodes.com Document number: DS35048 Rev. 2 - 2 NEW PRODUCT