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Electronics => Beginners => Topic started by: myf on May 02, 2019, 07:55:24 pm

Title: Looking for standard mosfet.
Post by: myf on May 02, 2019, 07:55:24 pm

Hello,

I like to play with npn and pnp transistors.

I use the mid-power bd139 and bd140 in to220 box, the low-power bc337 and bc327, and Darlington bc516 and bc517.
bd139 and bd140 are almost indestructible !

I want to discover n-channel  and p-channel mosfets but I don't know which I must choose.

The datasheet I am looking for is about :

  less than 50V, less than 10A , about Rdson = 30 or 50 miliOhm, an actually "close switch" at less than Vgs = 4V even for a 10A load, and a to220 box.
 
And I prefer to test cheap mosfet at about 3eur for 10pcs  on aliexpress.com.

I don't find any pair of n-channel and p-channel mosfets but there are bd139 and bd140. 

What do you think of these reference ? 
stp40nf10  type N  50A  100V 0.03ohm - 15A for 4V to-220 and
stp80pf55  type P  80A   55V 0.02ohm - 60A sous 5V to-220.

Maybe they are too big for my use ? Do you have better references to propose ?
Do you know a pair of reference : same datasheet for p-channel and n-channel ?

Might you confirm that no current inputs in the gate but the very very low capacity current.

Have a nice day !

F.

Title: Re: Looking for standard mosfet.
Post by: Jwillis on May 02, 2019, 08:35:09 pm

I won't find to many matched n and p type mosfets like you would with BJTs .This is because MOSFETs are almost always used in switching applications and p type are simply not needed in that type of application..You can't use most  MOSFETs or IGBT  in a linear fashion the same way you would with a BJT .Mosfet are either fully on or off and a switching pulse at the gate  is needed to control the source to drain.That of course is simplified.

If you want a general purpose MOSFETs to experiment with may I suggest the IRL3705 or N0604N .Both N type are common, very cheap and have lots of projects using them.As for P type I think I have one in my supply because I simply don't have any use for P type FETS

Title: Re: Looking for standard mosfet.
Post by: David Hess on May 03, 2019, 03:46:58 am

MOSFET complementary pairs differ much more than bipolar transistor complementary pairs because of a much greater difference in die size.  A p-channel device has either about twice the die area and power dissipation or twice the resistance and half the current rating.  So if you want a complementary MOSFET pair with equal dynamic characteristics, pick parts with the same voltage and power rating.

I would give some examples but Microchip's selection guides and documentation links are broken.