DESCRIPTION
   The ST1938 is a step-up DC/DC converter for white LED driver with over voltage protection.
   The device can driver one to four LEDs in series from a single cell Lithium Ion battery.
   Internal functions include current limiting; thermal shutdown; OVP and soft-start to prevent damage operate status. The ST1938 operates at 0.8MHz and from low input voltages as low as 1.5V; apply to Lithium-Ion powered systems. A low 95mV reference voltage minimizes power loss in the current setting resistor for better efficiency.
   The ST1938 is available in small package SOT-23-6L

FEATURES
● Current Source with Over Voltage
   Protection
● Fast 0.8MHz Switching Frequency
● High Efficiency up to 87%
● Drives up to Four LEDs From 3.2V
   Supply
● Drives up to Six LEDs From a 5V Supply
● Low Quiescent Current
● Disconnects LEDs in Shutdown Mode
● Internal Over Temperature and Current
   Limiting Shutdown Function
● Internal Soft-Start Circuit
● 36V Rugged Bipolar Switch
● Available in a Small SOT-23-6L Package

APPLICATIONS
● Battery Power Equipment
● Notebook Computers
● PDA
● Cellular Phone