AL3158FSG-7 Diodes Incorporated

AL3158 HIGH EFFICIENCY 1x/2x CHARGE PUMP FOR WHITE LED APPLICATIONS Description Pin Assignments The AL3158 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 AL3158 is capable of driving three groups of three LED channels at 20mA from a 2.7V to 5.5V input. The current sinks may be operated using three simple PWM dimming 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 IN OUT suited for small, battery-powered applications. AL3158 PWM dimming inputs are used to enable, disable device and dimming LED current with a fixed default current settings at 20mA or other factory programming options available. Each output of the AL3158 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 AL3158 is available in a lead-free, space-saving, thermally enhanced 20-pin 3 x 3mm QFN package. Features Applications V Range: 2.7V to 5.5V Mobile Phone White LED Backlighting and Indicators 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 Three simple PWM dimming for RGB or WLED Low transition threshold voltage typical 150 mV Dual-Mode 1x and 2x Charge Pump Drives up to 3 + 3 + 3 Channels of LEDs 1.2 MHz Constant Switching Frequency V short circuit and Thermal Protections OUT Soft Start for reducing inrush current Under Voltage Lockout Protection 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 AL3158 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 VOUT when un-used. D9 2 Current sink input #9. Connected to VOUT when un-used. EN1 3 Enable Pin 1 EN3 4 Enable Pin 3 EN2 5 Enable Pin 2 PGND 6 Charge Pump Switch Ground CN 7 Negative Terminal of Flying Capacitor VIN 8 Input Power Supply. Requires 2.2F capacitor between this pin and ground. 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 D6 18 Current sink input #6. Connected to V when un-used. OUT GND 17 Ground 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 AL3158 Diodes Incorporated www.diodes.com Document number: DS35047 Rev. 2 - 2 NEW PRODUCT