The selection of suitable MOSFETs is based on the core constraints of the application scenario, and is screened layer by layer according to the steps of "determining the technical route first, then sticking to key parameters, and finally verifying reliability and supply chain", to avoid performance waste or reliability risks caused by blindly pursuing extreme parameters.

Step 1: Lock in the core technology roadmap first
Firstly, based on the voltage level, switching frequency, and power density requirements of the application, directly lock in the corresponding mainstream MOSFET technology route and eliminate mismatched options from the root.

Step 2: Strictly control the three core key parameters
These three parameters directly determine the basic performance of the device, and sufficient margin must be reserved when selecting to avoid failure under actual working conditions:
Leakage source withstand voltage VDSS: At least 20% safety margin must be reserved. For example, in a 60V busbar scenario, a 100V withstand voltage device should be directly selected to avoid surge spikes directly penetrating the tube.
On resistance Rds (on): In low voltage and high current scenarios, milliohm level low Rds (on) devices should be preferred. At the same time, it should be noted that when the junction temperature rises to 125 ℃, Rds (on) will increase by 50%~80% compared to the nominal value of 25 ℃. When calculating the on loss, it must be calculated based on the value of the highest operating temperature.
Total gate charge Qg: Select devices with Qg<10nc for high-frequency scenarios with switching frequency>1MHz, devices with qg in the 10-30nc range for medium frequency scenarios between 100kHz and 1MHz, and devices with qg>30nC for low-frequency high current scenarios to avoid a sudden increase in the difficulty of driving circuit design.

Step 3: Match scene specific constraints
There are specific and mandatory requirements for applications in different industries, which must be confirmed during the selection phase
Vehicle scenario: The device must have AEC-Q101 vehicle certification, with a working temperature range of -55 ℃~150 ℃. Priority should be given to models that have been validated for mass production and vehicle installation, with compliance risk being the top priority.
Industrial high reliability scenarios: The key is to confirm the single pulse avalanche energy EAS and peak dv/dt tolerance, such as motor drive and battery protection scenarios. An avalanche tolerance of over 600mJ is required to withstand short-circuit surge impact.
Space limited scenario: Prioritize the DFN series small package and confirm the heat dissipation capability of the package. Large packages such as TO-220 are more suitable for high current working conditions above 100A.

Step 4: Verify the feasibility of supply chain and implementation
Priority should be given to models with stable stock and complete SPICE/thermal simulation models, so that losses and temperature rise can be simulated in advance before drawing, reducing later debugging costs.
Domestic alternative models can be prioritized for medium and low voltage scenarios. Currently, the localization rate of medium and low voltage MOSFETs has exceeded 60%, and the performance of some domestic devices has caught up with international brands. The supply cycle is more stable, and the cost advantage is more obvious.