Analog/PWM Dimmable High Power LED Direct AC Driver

The FL77944 is a direct AC line LED driver with a minimal number of external RC passive components. In normal configuration, one resistor is to adjust LED power, and one capacitor is to provide a stable voltage to an internal biasing shunt regulator.

The FL77944 provides phase-cut dimming with wide dimming range, smooth dimming control and good dimmer compatibility. It achieves high efficiency with high PF and low THD, which makes the FL77944 suitable for high-efficiency LED lighting systems. The FL77944 has a dedicated DIM pin which can be used with analog or digital PWM dimming. The FL77944 can also be used with a rheostat dimmer switch which is suitable for desktop or indoor lamps.

Operation of FL77944 admits driving higher-wattage systems, such as street lights and down lights, by simply parallel connecting the driver ICs.


  • The simplest Direct AC LED Driver with Only Two External RC Passive Component
  • Wide AC Input Range: 90~305 VAC
  • Four Integrated High-Voltage LED Constant Current Sinks of up to 150 mA (RMS) Capability
  • TRIAC Dimmable (Leading/Trailing Edge)
  • Rheostat Dimmable
  • Analog/Digital PWM Dimming Function
  • High Power Factor (above 0.98 in normal configuration)
  • Adjustable LED Power with an External Current Sense Resistor
  • Low Harmonic Content (THD under 20% in normal configuration)
  • Flexible LED Forward Voltage Configuration
  • Power Scalability with Multiple Driver ICs
  • Over-Temperature Protection (OTP)
  • SOP16 EP Package
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Product Product &
Eco Status
Unit Price/
1K Order
Packing Method Convention Package Marking
FL77944MX Full Production
Green as of Apr 2016
 China RoHS

SOIC 16L  -  Details
1.75 x 3.9 x 9.9mm,  TAPE REEL

PDF SOIC 16L  Drawing
Last Update: Jul 2016
Line 1$Y (Fairchild logo)
&Z (Plant Code)
&2 (2-Digit Date Code)

Line 2FL77944

ESD (HBM) 1000V

RƟJA 102°C/W

Moisture Sensitivity Level (MSL) 3

Max Reflow Temp 260

PDF China RoHS

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  • LED Lighting – High Power- Analog/PWM dimming
  • LED Lighting – Low Power – Analog/PWM dimming
  • LED Lighting – Mid Power- Analog/PWM dimming
  • Lighting
Application Note Description
AN-4190 PDFImprove Flicker Performance of Direct AC Driven LED Fixtures with Self Valley Fill
Last Update : 18-Jul-2016
AN-4189 PDFGuidance of Using Self Valley Fill Calculation Tool for FL77904/FL77944/FL77905
Last Update : 18-Jul-2016
AN-4188 PDFGuidance of Using LED Direct-AC Driver Design Tool for FL77904/FL77944/FL77905
Last Update : 18-Jul-2016
AN-5088 PDFDesigning for High Performance Commercial and Industrial Lighting Solution Using FL77944 High Power LED Direct AC Driver
Last Update : 20-Jun-2016

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