Selecting MOSFETs
To select a proper MOSFET in our design we should consider the following things. VDSS VGS Switching Speed Considerations for VDSS: The drain-source voltage VDSS rating is important in selecting MOSFETs. Application of a voltage exceeding VDSS might result in the destruction of a MOSFET. It is necessary to choose MOSFETs with a VDSS sufficiently higher than the voltage at which they will actually be used. High VDSS rated MOSFET's will have large on-state resistance, RDS(ON). A downside of using such MOSFETs is increased conduction loss. Generally, on-state resistance determines the upper limit of the drain current ID. Ensure that not only the loss calculated as ID 2×RDS(ON), the permissible power dissipation but also a temperature rise due to heating does not cause the device to exceed its operating temperature range. Considerations for VGS: The on-state resistance of MOSFETs is low when they operate in the linear region. Therefore, for ...