1 Features
1• Application Voltage Range: 80 VAC to 277 VAC • Capable of Controlling LED Currents
Greater than 1 A
• Adjustable Switching Frequency
• Low Quiescent Current
• Adaptive Programmable Off-Time Allows for
Constant Ripple Current
• Thermal Shutdown
• No Flicker at 120 Hz
• Low-Profile 10-Pin VSSOP Package
or 8-Lead SOIC Package
• Patented Drive Architecture

2 Applications
• Solid State Lighting
• Industrial and Commercial Lighting
• Residential Lighting

3 Description
The LM3444 is an adaptive constant off-time AC/DC
buck (step-down) constant current controller that provides a constant current for illuminating high
power LEDs. The high-frequency capable
architecture allows the use of small external passive
components. A passive PFC circuit ensures good
power factor by drawing current directly from the line
for most of the cycle, and provides a constant positive
voltage to the buck regulator. Additional features
include thermal shutdown, current limit and VCC
undervoltage lockout. The LM3444 is available in a
low profile 10-pin VSSOP package or an 8-lead SOIC package.