SparkFun MOSFET Power Switch and Buck Regulator (Low-Side)

Does your microcontroller need to control a high-voltage item, like a 12V LED strip, while also needing to be powered? Do you want to avoid having multiple power adapters and microcontrollers for your project? The MOSFET Power Switch and Buck Regulator (Low-Side) is one product SparkFun created for these exact needs. Power the board with up to 12V and control up to 10A, all while providing a reliable 3.3V to your control board.

This innovative board combines two circuits: an LMR14203 buck regulator configured to output 3.3V and an N-channel MOSFET (PSMN7R0-100BS) configured as a low-side switch. Additionally, a flyback diode is included on the load side for devices with back EMF. Simply pull the CTL pin low to activate the load.

Various connectors such as barrel jack, female header, and poke-home are provided to connect a power supply to your microcontroller of choice (Arduino, micro-bit, Raspberry Pi’s microcontroller) and load them together. VCC, 3.3V, CTL, and GND are also broken out through 2.54mm spaced PTHs for those who prefer to solder. Two LEDs (PWR_LED and ON_LED) indicate when there is 3.3V and whenever power is applied to the load. Jumpers are included on the back to disable the LEDs. A MEAS PTH jumper is also included for those interested in precisely measuring the current consumption of the system.

Note: While the MOSFET is rated to 100A/100V, it is recommended not to exceed 10A as the PCB polygon pours and traces become the limiting factor.

Features:

• Input Voltage Range: 4.5V to 12V
• LMR14203 Step Down Voltage Regulator
  • Configured to Output 3.3V/300mA
• PSMN7R0-1000BS N-Channel MOSFET
  • Configured as a Low-Side Switch
• Connectors
  • Input: 5.5mm x 2.1mm Barrel Jack (Center-Positive)
  • Output: Poke-Home Connectors
  • Control: 1x4 Female Headers
• 2.54mm-spaced PTHs
• Built-in Flyback Diode on Load
• LEDs
  • PWR
  • ON
• Jumpers
  • PWR_LED
  • MEAS
  • ON_LED
• Dimensions: 38.1mm x 38.1mm
• Weight: 9.9g

Documents:

• Schematic
• Eagle Files
• Board Dimensions
• Hookup Guide
• Fritzing Part
• Datasheet
  • LMR14203
  • PSMN7R0-100BS
• GitHub Hardware Repo