LM3445 - Triac Dimmable Offline LED Driver from the PowerWise® Family
Datasheet Packaging Samples & Pricing Eval. Boards Reliability Design Tools Reference Designs Knowledge Base

Features
•Triac dim decoder circuit for LED dimming
•Application voltage range 80VAC – 270VAC
•Capable of controlling LED currents greater than 1A
•Adjustable switching frequency
•Low quiescent current
•Adaptive programmable off-time allows for constant ripple current
•Thermal shutdown
•No 120Hz flicker
•Low profile 10 pin MSOP Package
• Patent pending drive architecture

General Description

The LM3445 is an adaptive constant off-time AC/DC buck (step-down) constant current controller designed to be compatible with triac dimmers. More...


Applications

•Retro Fit Triac Dimming
•Solid State Lighting
•Industrial and Commercial Lighting
•Residential Lighting
  Typical Application
*click for larger image


ParametersValues
Topology Buck
Input Min Voltage 70 Volt
Input Max Voltage 277 Volt
Output Range 15-100
Output Current 1000 mA
Efficiency (peak) 85 %
Special Features Triac Decode
Adjustable Output Yes
On/Off Pin Yes
Adj Switch Frequency Yes
Sync Pin No
Step-Down Yes
Step-Up No
Inverting No
Flyback No
RegType Switching Controller
Temperature Min -40 deg C
Temperature Max 125 deg C
Feedback Voltage 0.75 Volt
Automotive No
PowerWise Yes


Typical Performance

*click for larger image


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LM3445
AC Frequency 60 Hz 50 Hz
 
80.00 <=		 V in Lower
 V		  
<=		 V in Upper
 V		  
<= 260.00
Ambient Temperature  °C <= 100


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Additional Resources
Design Tools


Block Diagram

*click for larger image



Datasheet
RoHS Compliance Information Size in KbytesDate Click link below to Download
LM3445 Triac Dimmable Offline LED Driver 1201
Kbytes		 9-Oct-09 Download
LM3445 Triac Dimmable Offline LED Driver (Japanese)
 862 Kbytes   Download

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Package Availability, Models, Samples & Pricing
Part NumberPackageFactory Lead TimeModelsSamples &
Electronic
Orders		Budgetary PricingStd
Pack
Size		Package
Marking
Format
TypePinsSpec.MSL
Rating		Peak
Reflow		RoHS
Report		CAD
Symbols		WeeksQtyQty$US each
LM3445MMMINI SOIC10NOPB1260RoHS N/A Full productionN/A
Samples
Buy Now 		1K+$1.75reel
of
1000		ZXTT
SULB
6 weeksN/A
LM3445MMXMINI SOIC10NOPB1260RoHS N/A Full productionN/A
 
Buy Now 		1K+$1.75reel
of
3500		ZXTT
SULB
6 weeksN/A
LM3445-120VSMEVSmall Footprint/Most Efficient 110V Triac Dimmable Off-line LED Driver Evaluation BoardFull productionN/A
 
Buy Now 		1+$80.001-
8 weeksN/A
LM3445-220VEVAL220V Triac Dimmable Off-line LED Driver Evaluation BoardFull productionN/A
 
Buy Now 		1+$80.001-
8 weeksN/A

General Description

The LM3445 is an adaptive constant off-time AC/DC buck (step-down) constant current controller designed to be compatible with triac dimmers. The LM3445 provides a constant current for illuminating high power LEDs and includes a triac dim decoder. The dim decoder allows wide range LED dimming using standard triac dimmers. The high frequency capable architecture allows the use of small external passive components. The LM3445 includes a bleeder circuit to ensure proper triac operation by allowing current flow while the line voltage is low to enable proper firing of the triac. 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 under-voltage lockout.

Reliability Metrics

Part Number Process EFR Reject EFR Sample Size PPM LTA Rejects LTA Device Hours FITS MTTF (Hours)
LM3445MMABCD150XV1038680025950002736338335
LM3445MMXABCD150XV1038680025950002736338335

Note: The Early Failure Rates (EFR) were calculated as point estimate PPM based on rejects and sample size for EFR. The Long Term Failure Rates were calculated at 60% confidence using the Arrhenius equation at 0.7eV activation energy and derating the assumed stress temperature of 150°C to an application temperature of 55°C.

For more information on Reliability Metrics, please click here.


Design Tools

TitleSize in Kbytes Date Click link below to Download    
Article - #126: Dimming Techniques for Switched-Mode LED Drivers 386 Kbytes 30-Jul-2009 View Online Download  

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Reference Designs
•RD-172 - Off-Line TRIAC Dimmer LED Driver Reference Design

Application Notes

TitleSize in Kbytes Date Click link below to Download
AN-1935: Application Note 1935 LM3445 Off-Line TRIAC Dimmer LED Driver Demo Board 1716
Kbytes		 14-Apr-09 Download
AN-1935 (Japanese): Application Note 1935 LM3445 Off-Line TRIAC Dimmer LED Driver Demo Board
 2103 Kbytes   Download
AN-1978: Application Note 1978 LM3445 120VAC Small Evaluation Board 1235
Kbytes		 19-Aug-09 Download
AN-1995: Application Note 1995 LM3445 208-277V AC Non-Isolated Evaluation PCB 1409
Kbytes		 23-Oct-09 Download

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[Information as of 7-Nov-2009]