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N-Mosfet Can it be Posible Vds<Vgs?

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rhnrgn

rhnrgn

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Hello,

I am trying to trig my MCU's 5v level I/O with 24V signal. That is why i am planing to use n-mosfet.

I will connect 24v to gate of my mosfet, I/O to source of n-mosfet and 5 Volt to drain of mosfet. As you can see Vgs is grater than Vds.

I only need voltage level between 4V and 5V at the source of mosfet. Id is not important.

Is it posible?

I am planing to use IRLU014.

https://www.vishay.com/docs/91321/sihlr014.pdf

Thank You.
 

Any particular reason you need to do it this way. More usual to use an optocoupler with appropriate led resistor I would suggest around 2k2 to give around 10mA depending on which opto you use of course. This is a cheap, reliable and effective way to do it.
 
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    rhnrgn

    rhnrgn

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Hi,

If you apply 24V at the gate, you are exceeding the maximum Vgs rating of +/- 10V (as given in the datasheet). This will cause the oxide of the MOSFET to damage & the MOSFET will fail.

I recommend using a DC to DC SSR (Solid State Relay). Again it uses a optocoupler for isolation & switching.
 
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    rhnrgn

    rhnrgn

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Thank you. 4N35 will help me alot.

GrandAlf said:
Any particular reason you need to do it this way. More usual to use an optocoupler with appropriate led resistor I would suggest around 2k2 to give around 10mA depending on which opto you use of course. This is a cheap, reliable and effective way to do it.
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For N-Mosfet to ON, Vgs should be +ve and more than threshold value, in your case it is 2V. and max Vgs in this mosfet is 10V, so one thing is you should select a mosfet which will have Vgs more that 24V. or you can have volt. divider circuit to make 24v less than 10V.
 
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    rhnrgn

    rhnrgn

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