Low leakage electronic switch

[smjznj]

I am looking for an electronic switch which can switch on 10A from a 40V source with an off leakage of less than 200nA at temperatures below 50C. Most MOSFET data sheets list the IDSS at 1uA, although I suspect they actually conduct much less current in that situation. The configuration I have in mind would call for a P-channel MOSFET, but I am open to other solutions as well. Can anyone make a recommendation for this application? Of course space is at a premium as well. My luck getting feedback from semiconductor vendors has been poor, so if any helpful souls on this forum can provide inputs I would greatly appreciate it.

 

[VEBill]

There's a very similar question (and no good answer) here.

 

[OperaHouse]

Would it be possible to just drain off some of that leakage?

 

[jraef]

Don't know if this is applicable but...

What I've seen done is to use the transistor as the high speed switching device, but in the Off / Safe state (the typical reason for low leakage requirements), use a relay in series with it.

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[smjznj]

Thanks for the inputs all. I am not opposed to using a relay, but at least the ones I have found are rather large, both in footprint on a PWB and height above it. Tight packaging restraints limit the volume to as small as possible. 10A in a relay is typically rather large, at least what I have seen so far. Recommendations of a small relay for the V/I I need are welcome as well. The relay has the big advantage of 0 leakage, which I do like.

 

[IRstuff]

Well, just how small can you tolerate?

http://www.songle.com/en/pdf/20084141716341001.pdf

TTFN
faq731-376

 

[smjznj]

"Well, just how small can you tolerate?

http://www.songle.com/en/pdf/20084141716341001.pdf"

This is in the ballpark. I will definitely check it out, many thanks!!

 

[DHambley]

This may depend on whether your firm has a requirement to use worst case data sheet maximums or not. Typically for mil-aero that is required but not for many commercial applications. I have an IRFZ24 (60V) sitting on my bench right here. Putting a 10Meg resistor at the drain from 50V...let's see hmmm, not even 50mV at room temp so about 5nA is the leakage. I just blew hot air from my heat gun and it went up to about 600nA but it was too hot to touch. Sloppy quick experiment but, you get the point.

The data sheets always say 1uA or 25uA or whatever but realistically the typical part is much less and temperature is a major factor. I would say it depends on your application.

 

[smjznj]

That is a great test, thanks for posting the information. The Vishay data sheet for athat part is 25uA like you noted. I have considered screening the parts if necessary, as this is a very long standby life application, so I can not really rely on just hoping the parts have low leakage. It is good to have emperical data. I have been trying to get similar data from Vishay for over a month!!!

Semiconductors are still my favorite due to the much smaller form factor than a relay.