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 Drives Up to 5 Series White LEDs from 2.5V
z Drives Up to 8 Series White LEDs from 3.6V
z Up to 87% Efficiency
z 1.2MHz Fixed Switching Frequency
z Low 104mV Feedback Voltage
z Open Load Shutdown
z Soft Start/PWM Dimming
z SOT23-6 Packages

APPLICATIONS
z Cell Phones
z Handheld Computers and PDAs
z Digital Cameras
z Small LCD Displays