SDAA165 January   2026 TPS61287

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Key Parameters for Power MOSFET Selection
    1. 2.1 Static Characteristics
    2. 2.2 Dynamic Characteristics
    3. 2.3 Thermal Parameters
  6. 3Introduction to the MOSFET Selection Tool
    1. 3.1 Input MOSFET Parameters to Calculation Tool
    2. 3.2 Review the Results
  7. 4Calculator Tool MOSFET Selection Example and Bench Evaluation
  8. 5Summary
  9. 6References

2.1 Static Characteristics

Static parameters usually define the absolute maximum ratings and on-state performance of the switch.

  • Drain-Source Voltage (VDSS): This must be rated higher than the maximum voltage seen by the MOSFET. For a boost converter, this is at least the maximum output voltage (VOUT). A safety margin of 30-50% is recommended to account for voltage spikes caused by parasitic inductance.
  • Continuous Drain Current (ID): The MOSFET must handle the RMS and average input current. The RMS current in a boost converter is approximately equal to the input current (IIN).
  • On-Resistance (RDS(on)): This parameter directly determines the conduction losses (Pcond = IRMS2 × RDS(on)). A lower RDS(on) is desirable but often trades off with higher gate charge.
  • Gate threshold voltage (VGS(th)) and gate plateau voltage (Vplateau) or miller voltage (Vmiller ): these two voltages must be smaller than the MOSFET gate driving voltage so than the MOSFET can be fully turned on.