EUP2584AVIR1

EUP2584A W hite LED Step-Up Converter In Tiny SOT-23 Package DESCRIPTION The EUP2584A is a constant current step-up converter specifically designed to drive white LEDs. The Step-up converter topology allows series connection of the white LEDs so the LED currents are identical for uniform brightness. The EUP2584A switches at 1.1MHz, allowing the use of tiny external components. The input and output capacitor can be as small as 1µF, saving space and cost versus alternative solutions. A low 0.3V feedback voltage minimizes power loss in the current setting resistor for better efficiency. EUP2584A is enhanced with Soft-Start function and that could significantly reduce noise induced by capacitor. The EUP2584A is available in low profile SOT23-6 package. FEATURES 2.6V to 5.5V Input Range 27V Output with Over Voltage Protection High Efficiency :85 % Typical Internal Soft-Start PWM Dimming Control Internal High Power 30V MOSFET Switch Fast 1.1MHz Switching Frequency Small, Low-Profile Inductors and Capacitors SOT23-6 Package RoHS Compliant and 100% Lead (Pb)-Free APPLICATIONS Mobile Phone Digital Still Camera PDAs, Handheld Computers MP3 Players GPS Receivers Typical Application Circuit Figure 1. White LED Application DS2584A Ver1.0 Nov. 2007 1 EUP2584A Pin Configurations Package Type Pin Configurations SOT23-6 Pin Description PIN EN OUT IN LX GND FB SOT23-6 1 2 3 4 5 6 DESCRIPTION Chip Enable Pin. Connect to 1.4V or higher to enable device, 0.3V or less to disable device. Overvoltage Sense. When VOUT is greater than 27V, the internal N-channel MOSFET turns off until VOUT drops below 25V, then the IC reenters start. Connect a 1uF capacitor from OUT to GND. Input Supply Voltage Switch Pin. Connect inductor/diode here. Minimize trace area at this pin to reduce EMI. Common Ground Feedback Pin. Reference voltage is 0.3V. Connect cathode of lowest LED and resistor here. Calculate resistor value according to the formula: RFB=0.3/ILED DS2584A Ver1.0 Nov. 2007 2 EUP2584A Ordering Information Order Number EUP2584AVIR1 Package Type SOT23-6 Marking Operating Temperature range -40 °C to 125°C f0 □ □ □ □ EUP2584A □ □ □ □ Lead Free Code 1: Lead Free 0: Lead Packing R: Tape & Reel Operating temperature range I: Industry Standard Package Type V: SOT23 Block Diagram Figure 2. DS2584A Ver1.0 Nov. 2007 3 EUP2584A Absolute Maximum Ratings Supply Voltage ,VIN ----------------------------------------------------------------LX,OUT ----------------------------------------------------------------------------The Other Pins ---------------------------------------------------------------------Power dissipation, PD@ TA=25°C SOT23-6 ------------------------------------------------------------------------------Package Thermal Resistance SOT23-6,θJA ------------------------------------------------------------------------Maximum Junction Temperature --------------------------------------------------Lead Temperature (Soldering, 10sec.) --------------------------------------------Storage Temperature Range ---------------------------------------------------------0.3V to 6V -0.3V to 30V -0.3V to 6V 0.4W 250°C/W 125°C 260°C -65°C to 150°C Operating Conditions Junction Temperature Range ------------------------------------------------------- -40°C to 125°C Supply Voltage , VIN----------------------------------------------------------------- 2.6V to 5.5V Electrical Characteristics (VIN =3.6V, VOUT=18V, COUT=1µF, CIN=1µF, RSENSE=15Ω, TA=-40°C to 85°C. Unless otherwise noted. Typical values are at TA= 25°C) Symbol Parameter Supply Voltage Conditions VIN Rising VIN Falling No Switching VCC=6V, Continuous Switching VCC=6V, FB=1.3V, No Switching VCC=6V, VEN