There aren't many logic-level p-types to choose from. Supertex has a few. Spehro Pefhany suggested the IRF7425, which has 13 mill-ohms Rds(on) (max) at -2.5V, 8.5 mill-ohms at 4.5 volts. It's in an SO-8 package, about 85 cents US in 100's.
What are you looking for?
Fairchild FDV304P comes to mind.
Screw the MOS Fet, use a 2n3906 pnp transistor...
(See rs232 circiut in lower left)
Why don't you want to use a PNP BJT?
The BSS84 is one p-channel part spec'd at 5V.
Best regards, Spehro Pefhany
Zetex also makes some PMOS in TO92 with
Can anyone recommend a small P-channel MOSFET suitable for 5V logic level gate drive?
This is for an RS232-port-powered RS232 data output signal from a PIC. Source will go to +5V, gate to a PIC output, and the drain is resistively pulled-down to a negative rail. I did this years ago, but I can't remember what MOSFET I used. Farnell don't seem to specify any of their P-channel MOSFETs as being for logic level drive.
TIA Andrew.
Hello Spehro,
Yes, less cost.
One of my favorite parts but only if it really has to be a FET.
Regards, Joerg
Hello Andrew,
Then Spehro's suggestion (BSS84) should be the ticket. It's cheap.
Regards, Joerg
It's a one-off hobby project (GPIB-->RS232 using PIC16F84). Up to a few ohms would not be a problem for Rds(on), since the pull-down will be at least 1k. Package wise, I would prefer not to go surface mount, but I can handle them if necessary. I'll look at the IRF7425. Thanks.
Yes, I could do. I was thinking of saving the base current, but then I suppose it'll only be micro-amps.
Thanks, I'll look at that part.
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