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Newcomer to handling MOSFETS....

royalmp2001

May 20, 2014
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Hi Everyone,
I am new to handling and soldering Mosfets. If anyone can give advice to handling precautions please do. How susceptible are they to being destroyed by static? I will be using the IRF series.
Have soldered hundreds of CMOS 555 timers over the years without any precautions and have never had a problem. Are mosfets as resilient?
Thanks
 

Audioguru

Sep 24, 2016
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Cmos ICs have input protection against some (but not all) static electricity. Most Mosfets don't.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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I would recommend being careful.

Once soldered into a properly designed circuit you should be pretty safe, however prior to that, static charges can puncture the gate insulating layer.

As long as you are working in an area without significant static, using a soldering iron with a grounded tip, and grounding yourself to something reasonably regularly, life will be fine.

However, some devices are so sensitive that you need to physically short the leads before handling and soldering them, or alternatively working under a strict anti-static regime.

As mentioned, most ICs will have protection, so taking the sensible precaution of soldering the supply pins first is often all you need to do. Some mosfets have protected gates (often those designed for automotive use) and these are far more rugged in this respect than typical mosfets..
 

Chris Hill

Apr 17, 2017
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I was a MOSFET Application Engineer for 20 years, and I would largely agree with what *steve* says above. Most general-purpose, non-automotive MOSFETs actually don't have built-in gate protection, but the larger ones tend to be very robust anyway. Susceptibility to static damage tends to be linked to device size (and hence device capacitance). The larger devices in TO220, D2PAK, etc., will be more robust whereas very small ones (with very low capacitances) can be extremely sensitive and very easy to kill. To complicate matters further, there is always the possibility that static will cause a "walking wounded" failure whereby a device appears OK to begin with, but then fails unexpectedly for no apparent reason at some point in the future. So if you want to be really sure then I would take the antistatic precautions that *steve* describes, just to be on the safe side.
 
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