SIMPLE SWITCHER 42Vin, 0.3A Step-Down Voltage Regulator in SOT-23 - LMR14203


SIMPLE SWITCHER 42Vin, 0.3A Step-Down Voltage Regulator in SOT-23


The LMR14203 is a PWM DC/DC buck (step-down) regulator. With a wide input range from 4.5V-42V, it is suitable for a wide range of applications such as power conditioning from unregulated sources. They feature a low RDSON (0.9Ω typical) internal switch for maximum efficiency (85% typical). Operating frequency is fixed at 1.25 MHz allowing the use of small external components while still being able to have low output voltage ripple. Soft-start can be implemented using the shutdown pin with an external RC circuit allowing the user to tailor the soft-start time to a specific application.

The LMR14203 is optimized for up to 300 mA load current.

Additional features include: thermal shutdown, VIN under-voltage lockout, and gate drive under-voltage lockout. The LMR14203 is available in a low profile SOT-6L package.


  • Input Voltage Range of 4.5V to 42V
  • Output Voltage Range of 0.765V to 34V
  • Output Current up to 0.3A
  • 1.25 MHz Switching Frequency
  • Low Shutdown Iq, 16 µA Typical
  • Short Circuit Protected
  • Internally Compensated
  • Soft-Start Function
  • Thin SOT-23-6 Package (2.97 x 1.65 x 1mm)
  • Fully Enabled for WEBENCH® Power Designer

Performance Benefits

  • Tight Accuracy for Powering Digital ICs
  • Extremely Easy to Use
  • Tiny Overall Solution Reduces System Cost

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Parametrics Compare all products in Step-Down (Buck) Converter

Regulated Outputs (#)
Vin (Min) (V)
Vin (Max) (V)
Vout (Min) (V)
Vout (Max) (V)
Iout (Max) (A)
Switching Frequency (Max) (kHz)
Switch Current Limit (Typ) (A)
Iq (Typ) (mA)
Duty Cycle (Max) (%)
Soft Start
Special Features
Control Mode
Vref Accuracy (Typ) (%)
Operating Temperature Range (C)
Approx. Price (US$)
LMR14203 LMR14206
1     1    
4.5     4.5    
42     42    
0.765     0.765    
34     34    
0.3     0.6    
Buck     Buck    
1500     1250    
0.525     1.15    
1.3     1.3    
87     87    
Adjustable     Adjustable    
Internal     Internal    
Enable     Enable    
Current Mode     Current Mode    
2.5     2.5    
Catalog     Catalog    
-40 to 125     -40 to 125    
6SOT     6SOT    
0.90 | 1ku     0.99 | 1ku    

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New! Interactive Design
Click to instantly view a schematic, charts, Bill of Materials, and Operating Values.
    Min   Max   Range  
  Vin V 4.5 to 42.0V  
  Vout V 0.77 to 40.0V  
  Iout A ≤ 0.3A  
  Ambient Temp °C -40 to 125°C  
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