PFET Buck Controller for High Power LED Drives - LM3409


PFET Buck Controller for High Power LED Drives


Recommended alternative parts

  • TPS92515  -  2A current rating, integrated N-channel FET


The LM3409, LM3409-Q1, LM3409HV, and LM3409HV-Q1 are P-channel MOSFET (PFET) controllers for step-down (buck) current regulators. They offer wide input voltage range, high-side differential current sense with low adjustable threshold voltage and fast output enable/disable function and a thermally enhanced 10-pin, HVSSOP package. These features combine to make the LM3409 family of devices ideal for use as constant current sources for driving LEDs where forward currents up to 5 A are easily achievable.

The LM3409 devices use constant off-time (COFT) control to regulate an accurate constant current without the need for external control loop compensation. Analog and PWM dimming are easy to implement and result in a highly linear dimming range with excellent achievable contrast ratios. Programmable UVLO, low-power shutdown, and thermal shutdown complete the feature set.

For all available packages, see the orderable addendum at the end of the data sheet.


  • LM3409-Q1 and LM3409HV-Q1 are Automotive Grade Products: AEC-Q100 Grade 1 Qualified
  • 2-Ω, 1-A Peak MOSFET Gate Drive
  • VIN Range: 6 V to 42 V (LM3409, LM3409-Q1)
  • VIN Range: 6 V to 75 V (LM3409HV, LM3409HV-Q1)
  • Differential, High-Side Current Sense
  • Cycle-by-Cycle Current Limit
  • No Control Loop Compensation Required
  • 10,000:1 PWM Dimming Range
  • 250:1 Analog Dimming Range
  • Supports All-Ceramic Output Capacitors and Capacitor-less Outputs
  • Low-Power Shutdown and Thermal Shutdown
  • Thermally Enhanced 10-Pin, HVSSOP Package

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Parametrics Compare all products in LED Lighting - Illumination

Input Voltage (Type)
Vin (Min) (V)
Vin (Max) (V)
Iout (Max) (A)
Vout (Min) (V)
Vout (Max) (V)
Regulated Outputs (#)
Dimming Method
Switching Frequency (Min) (kHz)
Switching Frequency (Max) (kHz)
Iq (Typ) (mA)
Vref (V)
UVLO Thresholds On/Off (V)
Special Features
Operating Temperature Range (C)
Approx. Price (US$)
LM3409 LM3409-Q1 LM3409HV
DC/DC     DC/DC     DC/DC    
6     6     6    
42     42     75    
5     5     5    
1.24     1.24     1.24    
42     42     75    
1     1     1    
Buck     Buck Controller     Buck    
Inductive     Inductive     Inductive    
50     50     50    
2000     2000     2000    
2     2     2    
0.248     0.248     0.248    
3.73 / 3.44     3.73 / 3.44     3.73 / 3.44    
Adjustable Switch Frequency
Thermal Shutdown    
Adjustable Switch Frequency
Thermal Shutdown    
Adjustable Switch Frequency
Thermal Shutdown    
Catalog     Automotive     Catalog    
-40 to 125     -40 to 125     -40 to 125    
10MSOP-PowerPAD     10MSOP-PowerPAD    
0.70 | 1ku     0.88 | 1ku     0.75 | 1ku    

Other qualified versions of LM3409

Version Part Number Definition
Automotive LM3409-Q1 Q100 devices qualified for high-reliability automotive applications targeting zero defects

WEBENCH® Designer LM3409

  V in Lower V in Upper
6.0 ≤  V  V ≤ 42.0
Ambient Temp  °C ≤ 125°C
Light Output (optional)  Lumens