The basic key checks for using a Mosfet in a circuit design: Drain-source voltage Absolute max rating is well above the max voltage being switched.Allow for maximum voltage peeks and pulses that may be present. Gate-source voltage The voltage you will apply to the gate is within this absolute max rating. Drain current (continuous and […]

Mosfet providing polarity protection without diode voltage drop For a P channel mosfet, whenever the Gate voltage is lower than the (Source Voltage – Gate Threshold voltage) the MOSFET conducts. If the gate voltage is higher than this, it does not conduct. The greater the voltage difference from the Source the more the MOSFET can […]

The characteristics of paralleled mosfets will not be guaranteed to be exactly the same due to manufacturing differences, tolerances etc, so your design needs to allow for this. Heatsinking Paralleled mosfets should be placed close together and use the same heatsink so they are thermally matched. Current Sharing Resistor You typically need to use a source […]

Basic MOSFET Selection Rules / Checks The Drain to Source max voltage rating (max Vds) determines the maximum voltage you can switch. The Gate threshold voltage determines the voltage difference you need to apply to the gate to make the mosfet conduct. The Gate to Source max voltage (max Vgs) is a critical factor that must not be exceeded (even […]