TO-220 BJT as low leakage diode?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I have a non-audio application which could use a low leakage diode.

I was just googling this subject when I came across a discussion of using BJT's B-C junction for a low leakage diodes. The examples were all small devices though. I need a little bigger current handling as well.

Would this tip work just as well with a TO-220 BJT? Something anybody has in their parts box, say a TIP-41? How about anything else in the part box, like a MOSFET, etc.?
 
1A forward current with 10mA reverse leakage seems to be easy to attain with pretty much any competent diode currently available. A basic 1N4004 will handle 1A forward current and has a max. leakage spec at 100ºC of 50µA, and a typical 100ºC spec of 1µA. I don't know how hot "hot" is in your world, but these specs at 100ºC are pretty nice, and are a lot better if you can run cooler. You could pore through a lot of data sheets and maybe optimize this, but a gumball diode should be able to easily beat this spec.
 
I don't have an exact spec because the lower the leakage the better the circuit performs, but let's say 1A forward current and 10mA leakage (hot) would be great.
Even germanium OA- series could probably fit the bill, but out of curiosity, I measured a single sample: a BD201 from Philips, because I am completely sure about its origin, and at 60V Vcb and 27°C (present temperature here), the leakage current is 30nA. Not super-low, but worth considering, especially taking into account that it is just a single randomly selected type. By screening more types, you could probably find much better candidates
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.