MOSFET question

I was just looking those up yesterday (just research, no experience). For example, the BSS84W (although p-channel) from Diodes Inc. Has a max Vgs(th) of 2v, and about 1.1 ohms typ "on" at 2.5v (my design voltage). Try looking at others in that family.

Try the Fairchild NDS331N for up to 1.3 A current. Gate switches at TTL levels.

Mario C.

mc wrote:

This topic came up not long ago. Boki was trying to figure how to drive some LED's from a low voltage circuit.

IIRC, there were some decent, cheap candidates aired.

OK, I just went and looked. Short answer, try the BSS138.

For further reading, here is the message ID and subject for the first post:

Message-ID: subject: 2N7000's Vgs

HTH

--Mac

At first sight that doesn't look any different from the 2N7000. The manufacturer doesn't publish specifications for Vgs lower than 4.5.

What I see here is a point of unreliability. You could choose a type that

I use the ON Semi BSS138LT1 for low voltage applications. The data sheet specs max rDS(on) of 10 ohms at VGS = 2.75V, from -40c to +85c.

================================

Greg Neff VP Engineering

Another good N-channel MOSFET that I have been using lately is the IRLML2502. (DigiKey has them for 77 cents.) When turned on with 3v on the gate, the resistance from Drain to Source is only .035 ohms! Will allow up to 4 amps Drain to Source.

-Craig

Thanks, I'll check it out.

Anything like that in TO-92 or TO-220 so that it can be used on breadboards?

The closest thing to a TO-92 I see is the IRLD024PBF in a 4 pin DIP package:

IR makes quite a few TO-220AB package logic level N channel mosfets. E.G.

etc.

Well, you didn't specify too clearly what you were trying to do.

The Vgs(th) max for the BSS138 is 1.5V, and that is with 1mA. The min transconductance is 0.12 A/V, so with Vgs = 3V, you could argue that that will take you pretty far into the "on" region, depending on what you are trying to do.

Best regards, Mac