Hi
I would like to build an isolated 4-20mA receiver and have found an example of a circuit that fits my needs perfectly on page 9 of the IL300 application note http://www.vishay.com/docs/83710/appn54.pdf.

The problem I have is that it uses a TN0201L N Channel MOSFET which now obsolete. Can anyone recommend a replacement that I could use in this circuit? I've tried matching the specification but with little luck so far.

 

The first AN I pulled up was from Vishay, and there's no MOSFET on page 9. Please post the relevant schematic.

Oh wait, maybe I found it ?:

 

Yep that's the one.

 

I think any logic-level N-type MOSFET with a similar or higher current rating should work fine.

 

Many thanks for your help Wayneh.

 

Go ahead and pick something and let the pros here offer comments. They might see something we've missed.

 

OK, so I'm now looking at using an IRFD210PBF as a replacement.

 

http://english.electronica-pt.com/db/cross-reference.php?ref=TN0201L

 

That's not a logic level MOSFET. It's a "regular" one and needs too high a voltage on its gate to turn fully on, with the mediocre voltage of that schematic.

Maybe VN10LP or VN2222? Or RFP30N06LE or FQP30N06L.

I'm sure folks here have other favorites.

 

Just as 2N2222 is an "any" NPN transistor, I usually use 2N7000 MOSFETs. Cheap, available in both SOT23 (2N7002) and TO92 cases. Typical switch voltage 2.1 V

 

I was going to mention the popular 2N7000, but isn't it a regular (not logic) MOSFET?

 

I see where I went wrong with the first alternative I thought about using (embarrassing really).

When initially faced with the datasheet my eyes glazed over but, in this application, there aren't very many 'important' parameters that I need consider.

Thanks guys for the help.