Low cap PMOS

[Fred Bartoli]

I think it was J.L. who gave a few weeks/months ago the reference of a
nice small PMOS with IIRC half the parasitics of a BSS84, but I can't
find it...

John, can you give it again?

Thanks.

 

[Joerg]

This one?

https://dl.dropbox.com/u/53724080/Circuits/Current_Sources/Isrc_5.JPG

That's an OnSemi/Sanyo part.

www.onsemi.com/pub/Collateral/EN6619-D.PDF

Just be careful with product development. Much of the stuff with
Japanese ancestry is going unobtanium these days. Digikey has lots of
the 5LP01M though.

There's also the uPA610 dual, but also of Japanese origin and it's
currently zero stock in the US.

 

[Fred Bartoli]

John Larkin a écrit :

This one?

https://dl.dropbox.com/u/53724080/Circuits/Current_Sources/Isrc_5.JPG

That's an OnSemi/Sanyo part.

www.onsemi.com/pub/Collateral/EN6619-D.PDF

I think so. Thanks.

One thing I didn't notice is that they seem to have built-in awfully
high gate resistance... (see the loooong switching times)

 

[Joerg]

John Larkin a écrit :

I think so. Thanks.

One thing I didn't notice is that they seem to have built-in awfully
high gate resistance... (see the loooong switching times)

That's on account of the built-in gate-source zener. You'll want a FET
without that. Slim pickens, as they say over here, not too much to pick
from.

If there is the slightest chance to swing this circuit to N-channel then
by all means I'd do it.

 

[Mr Stonebeach]

I think it was J.L. who gave a few weeks/months ago the reference of a
nice small PMOS with IIRC half the parasitics of a BSS84, but I can't
find it...

John, can you give it again?

Thanks.

I have used FDV302P in some cryogenic work,
it also has pretty low Ciss.

Regards,
Mikko

 

[Joerg]

That's on account of the built-in gate-source zener. You'll want a FET
without that. Slim pickens, as they say over here, not too much to pick
from.

If there is the slightest chance to swing this circuit to N-channel then
by all means I'd do it.

Ooops, sorry, I read gate capacitance but that's not what you meant.

 

[Fred Bartoli]

Joerg a écrit :

Ooops, sorry, I read gate capacitance but that's not what you meant.

Ah, I wondered what the zener had to do with the gate resistance