What mosfet?

[andy257]

Hi All,

Can anyone recommend me an N type mosfet that is switched hard on at 3.3V. Ive had a search but all i seem to find are logic fets which switch at 5V.

Thanks

 

[crutschow]

It's difficult to build MOSFETs with low threshold voltage, so there may not be any available with 3.3V Vgs for full turn-on. But perhaps you could use a 3.3V to 5V logic converter to drive the gate of a 5V MOSFET.

 

[Bob Scott]

The 5V FET might work fine. Look at the data sheet and find the graph showing Gate voltage vs Drain current. From the graph, find the required gate voltage that matches the maximum drain current that your circuit requires. Most likely, this voltage is less than 5V.

 

[RCinFLA]

You did not specify breakdown voltage or drain current needed.

Cell phone use MOSFET's for 3 v Vgs but are limited to Vds of about 30 vdc and 2-3 amps. For example, there is likely a P-ch in battery pack for low voltage cutout on LiIon battery that produces about 20 mohms with -2.5 vdc of Vgs.

NTA4153N, NTE4153N are N-ch small sig capable of about 900 mA with a max Vds of 20 vdc. About 200 mohms with 2.5v Vgs.