Using mosfet as a switch

[purpleanger]

I wanna design the switch using the mosfet.
gate voltage is about 2.5V.

What kind of MOSFET can I use?

Thanks.

 

[umesh49]

Its depends.. what is your application for switch?

 

[mister_rf]

You may use a P-channel power MOSFET
https://www.fairchildsemi.com/ds/FD/FDS6679AZ.pdf
https://www.fairchildsemi.com/ds/FD/FDS4465_F085.pdf



Read here:

**broken link removed**-

 

[Eric Best]

You may use a P-channel power MOSFET

In my opinion if purpleanger wrote "...gate voltage is about 2.5V..." (i.e. V_GS being a positive voltage), then, strictly speaking, the MOSFET should be N-channel. And I am yet adding (because a switch is to be designed): it has to be an enhanced mode type (for it to be switched off "without" V_GS applied, i.e. when V_GS = 0V, or even when V_gs < 0V).
The concrete type to be used depends on the required switched current/applied voltage, etc. in the switching circuit, these requirements weren't specified by purpleanger.

 

[atripathi]

What is voltage & current you want to "Switch". Based on that you can select a MoSFET from any semiconductor manufacture site. Few other things to note:

Keep a good margin on VDS voltage rating.
MOSFET current handling capacity significantly reduce with temperature, be default ratings are mentioned at 25C.
Lastly you want to consider package type.

 

[Tahmid]

You should look to use a logic level MOSFET with a gate threshold voltage low enough. Power MOSFETs require around 8 to 10 volts to completely turn on.
What is your current requirement and the max voltage on the MOSFET drain? From that it will be easier to choose a MOSFET.

Hope this helps.
Tahmid.