If I have a P-channel mosfet and I want it to operate with Vgs much more than absolute maximum ratings what's the best solution which can I do? I thought that a zener between gate and source might be a good solution but, if I go through this what would be happened if the zener does not start to conduct immediately and the mosfet receive the whole amount of voltage even for a few micro seconds until the zener starts to conduct?

The mosfet is intended for reverse polarity protection.

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    \$\begingroup\$ What is driving the gate? Remember the gate capacitance prevents the gate voltage from changing instantaneously. \$\endgroup\$ – The Photon Dec 12 '16 at 15:43
  • \$\begingroup\$ I thought that as well. That might mean that I could add more capacitance by adding a capacitor in parallel in the gate-source? \$\endgroup\$ – MrBit Dec 12 '16 at 15:51
  • \$\begingroup\$ The zener itself will also add capacitance. So you need to know the impedance of the source driving the gate to know whether you need further protection. Please edit your question to share that information. \$\endgroup\$ – The Photon Dec 12 '16 at 15:52
  • \$\begingroup\$ The mosfet is intended for reverse polarity protection. \$\endgroup\$ – MrBit Dec 12 '16 at 16:10

The zener will work fine, and it's a commonly-used solution. You'll be driving the zener+gate through a resistor that limits the current to a safe level for the zener, and that resistance, together with the capacitance of the zener and the MOSFET, will act as a low-pass filter that helps protect against fast transients.

  • \$\begingroup\$ This means no extra capacitor in parallel to zener needed, right? \$\endgroup\$ – MrBit Dec 12 '16 at 16:33

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