How to select a mosfet for your design || N-MOSFET || IRF740

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#mosfet #mosfetselection #choosemosfet
In this video mosfet selection is explained. After watching this video you will be able to select a mosfet for your design.

Thumb Rule in mosfet selection-
1. Vds - 1.5 to 2 times of rated Vds. Also check the de-rating curve of Vds vs temperature.
2. Id - Minimum 3 times of your rated drain current. Incase of higher ambient temperature lets say 85C/105C you must see the Id vs Temperature curve and if needed increase the Id to 5 times of rated drain current.
3. Vgs - Should be the value where Rds(on) is lower. Let say if lower mosfet Rds(on) is rated for 10V (Vgs) then bias your mosfet to operate the mosfet at Vgs = 10V in order to achieve the optimum thermal performance.
4. Vgs(th) is another parameter to decide the minimum ON voltage for mosfet based on your application.
4. Choose mosfet with lower Rds(on). Higher Rds(on) leads the higher temperature rise of mosfet.
5. Always look for mosfet switching characteristics e.g Gate charge, Input and output characteristics of mosfet. Lower input and output capacitor will give higher switching speed of the mosfet.
Input capacitor will help you in sizing the mosfet gate resistor.
6. Always look for safe operating curve(SOA) of mosfet for stability and avoid thermal runway of the mosfet.
7. Check mosfet power dissipation and verify if it meets your design requirement. It is recommended to de-rating curve of power dissipation with respect to ambient temperature.
8. Calculate the temperature rise of the mosfet above ambient. Thermal parameter of mosfet will help to calculate temperature rise in mosfet.
9. Check mosfet body diode characteristics per your current requirement.

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