Home Power management LED drivers Illumination LED drivers

LM3445

ACTIVE

Triac dimmable offline LED driver

Product details

Input voltage type AC/DC Topology Buck, Flyback Vin (min) (V) 8 Vin (max) (V) 12 Vout (max) (V) 60 Vout (min) (V) 9 Iout (max) (A) 2 Iq (typ) (mA) 2 Features Adjustable Switch Frequency, Enable/Shutdown, Thermal shutdown Operating temperature range (°C) -40 to 125 Dimming method Forward Phase (Triac), PWM, Reverse Phase Number of channels 1 Rating Catalog
Input voltage type AC/DC Topology Buck, Flyback Vin (min) (V) 8 Vin (max) (V) 12 Vout (max) (V) 60 Vout (min) (V) 9 Iout (max) (A) 2 Iq (typ) (mA) 2 Features Adjustable Switch Frequency, Enable/Shutdown, Thermal shutdown Operating temperature range (°C) -40 to 125 Dimming method Forward Phase (Triac), PWM, Reverse Phase Number of channels 1 Rating Catalog
SOIC (D) 14 51.9 mm² 8.65 x 6 VSSOP (DGS) 10 14.7 mm² 3 x 4.9
  • TRIAC Dim Decoder Circuit for LED Dimming
  • 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 120-Hz Flicker
  • Low Profile 10-Pin VSSOP Package or 14-Pin
    SOIC
  • Patented Drive Architecture
  • TRIAC Dim Decoder Circuit for LED Dimming
  • 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 120-Hz Flicker
  • Low Profile 10-Pin VSSOP Package or 14-Pin
    SOIC
  • Patented Drive Architecture

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.

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.

Download View video with transcript Video

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

LM3445EVM-695 — LM3445 120Vac Valley Fill Buck Triac Dimmable LED Driver Evaluation Module

The LM3445EVM-695 implements a dimming solution using the LM3445 integrated circuit from Texas Instruments. The LM3445 is an adaptive constant off-time AC/DC buck constant current controller with built in phase dimming decoder. Line cycles are analyzed continuously by an internal low power digital (...)

User guide: PDF
Not available on TI.com
Simulation tool

PSPICE-FOR-TI — PSpice® for TI design and simulation tool

PSpice® for TI is a design and simulation environment that helps evaluate functionality of analog circuits. This full-featured, design and simulation suite uses an analog analysis engine from Cadence®. Available at no cost, PSpice for TI includes one of the largest model libraries in the (...)
Reference designs

PMP30439 — 230 V in to 180 V out at 200 mA constant-current LED driver reference design

This reference design is a low-side Buck (the output voltage is referenced to the positive DC input (+Vin node), not to the GND node). The controller drives a LED string up to 180V with 200mA constant current. The low-side Buck topology simplifies the schematic thanks to direct-driving of the FET, (...)
Test report: PDF
Schematic: PDF
Package Pins CAD symbols, footprints & 3D models
SOIC (D) 14 Ultra Librarian
VSSOP (DGS) 10 Ultra Librarian

Ordering & quality

Information included:
  • RoHS
  • REACH
  • Device marking
  • Lead finish/Ball material
  • MSL rating/Peak reflow
  • MTBF/FIT estimates
  • Material content
  • Qualification summary
  • Ongoing reliability monitoring
Information included:
  • Fab location
  • Assembly location

Support & training

TI E2E™ forums with technical support from TI engineers

Content is provided "as is" by TI and community contributors and does not constitute TI specifications. See terms of use.

If you have questions about quality, packaging or ordering TI products, see TI support. ​​​​​​​​​​​​​​

Videos