PT4103

PT4103 White LED Step-Up Converter GENERAL DESCRIPTION The PT4103 is a step-up DC/DC converter designed for driving up to 8 white LEDs in series from a single cell Lithium Ion battery with constant current. Because it directly regulates output current, the PT4103 is ideal for driving light emitting diodes (LEDs) whose light intensity is proportional to the current passing through them, not the voltage across their terminals. A single external resistor sets LED current between 5mA and 20mA, which can then be easily adjusted using either a DC voltage or a pulse width modulated (PWM) signal. Its low 104mV feedback voltage reduces power loss and improves efficiency. The OV pin monitors the output voltage and turns off the converter if an over-voltage condition is present due to an open circuit condition. The PT4103 is available in SOT23-6 packages. FEATURES z z z z z z z z Drives Up to 5 Series White LEDs from 2.5V Drives Up to 8 Series White LEDs from 3.6V Up to 87% Efficiency 1.2MHz Fixed Switching Frequency Low 104mV Feedback Voltage Open Load Shutdown Soft Start/PWM Dimming SOT23-6 Packages APPLICATIONS z z z z Cell Phones Handheld Computers and PDAs Digital Cameras Small LCD Displays ORDERING INFORMATION PACKAGE SOT23-6 TEMPERATURE RANGE -40 oC to 85 oC ORDERING PART NUMBER PT4103B23F TRANSPORT MEDIA Tape and Reel 3000 units MARKING 4103 TYPICAL APPLICATIONS KEY PERFORMANCE CHART Efficiency vs n(LED) 90.00% 85.00% 3LED 4LED 5LED 6LED 80.00% 7LED 8LED 75.00% 5 10 15...