EUP2571VBIR1

EUP2571 W hite LED Step-Up Converter In Tiny SOT-23 Package DESCRIPTION The EUP2571 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 EUP2571 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 0.25V feedback voltage minimizes power loss in the current setting resistor for better efficiency. The EUP2571 is available in low profile SOT23-5, SOT23-6 package. FEATURES 2.6V to 5.5V Input Range 26V Output with Over Voltage Protection High Efficiency :85 % Typical PWM Dimming Control Internal High Power 30V MOSFET Switch Fast 1.1MHz Switching Frequency Small, Low-Profile Inductors and Capacitors SOT23-5,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 DS2571 Ver1.1 May. 2007 1 EUP2571 Typical Application Circuit (continued) Figure 2. 5V to 9V/300mA Step-Up Application Pin Configurations Package Type Pin Configurations Package Type Pin Configurations SOT23-5 SOT23-6 Pin Description PIN LX GND FB EN IN OUT SOT23-5 1 2 3 4 5 SOT23-6 1 2 3 4 6 5 DESCRIPTION Switch Pin. Connect inductor/diode here. Minimize trace area at this pin to reduce EMI. Common Ground Feedback Pin. Reference voltage is 0.25V. Connect cathode of lowest LED and resistor here. Calculate resistor value according to the formula: RFB=0.25/ILED Chip Enable Pin. Connect to 1.4V or higher to enable device, 0.4V or less to disable device. Input Supply Voltage 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. DS2571 Ver1.1 May. 2007 2 EUP2571 Ordering Information Order Number EUP2571VBIR1 EUP2571VCIR1 Package Type SOT23-5 SOT23-6 Marking Operating Temperature range -40 °C to 125°C -40 °C to 125°C V0 □ □ □ V0 □ □ □ EUP2571 □□ □ □ □ Lead Free Code 1: Lead Free 0: Lead Packing R: Tape & Reel Operating temperature range I: Industry Standard Package Type V: SOT23 VB: SOT23-5 VC: SOT23-6 Block Diagram Figure 3. DS2571 Ver1.1 May. 2007 3 EUP2571 Absolute Maximum Ratings Supply Voltage ,VIN ----------------------------------------------------------------- -0.3V to 6V LX,OUT ----------------------------------------------------------------------------- -0.3V to 30V The Other Pins ---------------------------------------------------------------------- -0.3V to 6V Power dissipation, PD@ TA=25°C SOT23-6 ------------------------------------------------------------------------------- 0.4W Package Thermal Resistance SOT23-6,θJA ------------------------------------------------------------------------- 250°C/W Maximum Junction Temperature --------------------------------------------------- 125°C Lead Temperature (Soldering, 10sec.) --------------------------------------------- 260°C Storage Temperature Range ------------------------------------------------------- -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=12V, COUT=1µF, CIN=1µF, RSENSE=12Ω, TA=-40°C to 85°C. Unless otherwise noted. Typical values are at TA= 25°C) Symbol UVLO ICC1 ICC2 ICC3 Oscillator Fosc Dmax Parameter Supply Voltage Under voltage Lock Out Maximum Output Voltage Supply Current Quiescent Current Shut Down current Operation Frequency Maximum Duty Cycle TA=25℃ Conditions VIN rising or falling VCC=6V, Continuous Switching VCC=6V, FB=1.3V, No Switching VCC=6V, VEN