EUP2518OIR1

EUP2518 W hite LED Step-Up Converter In TSOT-23 Package DESCRIPTION The EUP2518 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 EUP2518 switches at 1.1MHz, allowing the use of tiny external components. The output capacitor can be as small as 0.22uF, saving space and cost versus alternative solutions. A low 104mV feedback voltage minimizes power loss in the current setting resistor for better efficiency. EUP2518 is enhanced with Soft-Start function and that could significantly reduce noise induced by capacitor. The EUP2518 is available in low profile TSOT23-6 package. FEATURES 2.6V to 5.5V Input Range 27V Output with Over Voltage Protection High Efficiency :87 % Typical Internal Soft-Start PWM Dimming Control Internal High Power 30V MOSFET Switch Fast 1.1MHz Switching Frequency Small, Low-Profile Inductors and Capacitors TSOT23-6 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 DS2518 Ver1.0 Mar. 2008 1 EUP2518 Pin Configurations Package Type Pin Configurations TSOT23-6 Pin Description PIN LX GND FB EN OUT IN TSOT23-6 1 2 3 4 5 6 DESCRIPTION Switch Pin. Connect inductor/diode here. Minimize trace area at this pin to reduce EMI. Common Ground Feedback Pin. Reference voltage is 104mV. Connect cathode of lowest LED and resistor here. Calculate resistor value according to the formula: RFB=104/ILED 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 0.22uF capacitor from OUT to GND. Input Supply Voltage DS2518 Ver1.0 Mar. 2008 2 EUP2518 Ordering Information Order Number EUP2518OIR1 Package Type TSOT23-6 Marking Operating Temperature Range -40 °C to 85°C 50 □ □ □ □ EUP2518 □ □ □ □ Lead Free Code 1: Lead Free 0: Lead Packing R: Tape & Reel Operating temperature range I: Industry Standard Package Type O: TSOT Block Diagram Figure 2. DS2518 Ver1.0 Mar. 2008 3 EUP2518 Absolute Maximum Ratings Supply Voltage ,VIN ----------------------------------------------------------------LX,OUT ----------------------------------------------------------------------------The Other Pins ---------------------------------------------------------------------Package Thermal Resistance TSOT23-6,θJA ----------------------------------------------------------------------Maximum Junction Temperature --------------------------------------------------Lead Temperature (Soldering, 10sec.) --------------------------------------------Storage Temperature Range ---------------------------------------------------------0.3V to 6V -0.3V to 30V -0.3V to 6V 220°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=0.22µF, CIN=1µF, RFB=5.1Ω, 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