SM74301 (ACTIVE)

100V, 350 mA Constant On-Time Buck Switching Regulator



The SM74301 is a Constant On-Time (COT) Buck Switching Regulator which operates at a low minimum input voltage of 6V and does not require a minimum load current as some other COT parts.

The SM74301 Step Down Switching Regulator features all of the functions needed to implement a low cost, efficient, Buck bias regulator. This high voltage regulator contains a 100V N-Channel Buck Switch. The device is easy to implement and is provided in the VSSOP-8 and the thermally enhanced WSON-8 packages. The regulator is based on a control scheme using an ON time inversely proportional to VIN. This feature allows the operating frequency to remain relatively constant. The control scheme requires no loop compensation. An intelligent current limit is implemented with forced OFF time, which is inversely proportional to Vout. This scheme ensures short circuit control while providing minimum foldback. Other features include: Thermal Shutdown, VCC under-voltage lockout, Gate drive under-voltage lockout, Max Duty Cycle limiter, and a pre-charge switch.


  • Renewable Energy Grade
  • Operating Input Voltage Range: 6V to 95V
  • Integrated 100V, N-Channel Buck Switch
  • Internal Start-Up Regulator
  • No Loop Compensation Required
  • Ultra-Fast Transient Response
  • On Time Varies Inversely with Input Voltage
  • Operating Frequency Remains Constant with Varying Line Voltage and Load Current
  • Adjustable Output Voltage from 2.5V
  • Highly Efficient Operation
  • Precision Internal Reference
  • Low Bias Current
  • Intelligent Current Limit
  • Thermal Shutdown


  • VSSOP-8
  • WSON-8 (4mm x 4mm)

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Typical Applications

  • High Voltage Photovoltaic Systems
  • Non-Isolated Telecommunication Buck Regulator
  • Secondary High Voltage Post Regulator

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