PFET Buck Controller for High Power LED Drives - LM3409


PFET Buck Controller for High Power LED Drives


The LM3409/09N/09HV/09Q/09QHV 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 VSSOP-10 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 5A 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.

The LM3409/09Q/09N have an operational input voltage range up to 42V, while the LM3409HV/QHV are high voltage options with an input voltage range up to 75V. The LM3409/09HV/09Q/09QHV come in a thermally enhanced 10-lead VSSOP package, while the LM3409N comes in a 14-lead PDIP package. The LM3409Q/LM3409QHV are automotive grade products that are AEC-Q100 grade 1 qualified.


  • LM3409Q/LM3409QHV is an Automotive Grade Product That is AEC-Q100 Grade 1 Qualified
  • 2Ω, 1A Peak MosFET Gate Drive
  • VIN Range: 6V to 42V (LM3409/LM3409Q/LM3409N)
  • VIN Range: 6V to 75V (LM3409HV/LM3409QHV)
  • 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 VSSOP-10 Package
  • Dual Inline Package (LM3409N)

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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     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
6.0 <=

V in Lower

V in Upper
<= 42.0
Ambient Temp  °C <= 125
Light Output (optional)  Lumens

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