Si9410BDY mosfets - are they particularly ESD sensitive?
Bookmark this page:
 Yahoo!
 Google
 Windows Live
 del.icio.us
 digg
 Netscape
|
|
|||||||||||||||||||||||||||||||
|
Posted by Den on August 12, 2008, 1:40 am
Please log in for more thread options I'm having some probs repairing some gear with Si9410BDY SO-8 pkg mosfets in them. The FET will appear to be faulty - replaced it - still no go......replace it again - it works - WTF! It's happened too many times to be finger trouble or gremlins. I thought maybe it was ESD - even though I'm working on a grounded mat with a grounded iron. Are they particularly sensitive?? Data sheet: http://www.vishay.com/docs/72269/72269.pdf cheers. D. | |||||||||||||||||||||||||||||||
|
Posted by MooseFET on August 12, 2008, 9:55 am
Please log in for more thread options > I'm having some probs repairing some gear with Si9410BDY SO-8 pkg mosfets=
in
> them.
it
> > The FET will appear to be faulty - replaced it - still no go......replace= > again - it works - WTF!
ded
> > It's happened too many times to be finger trouble or gremlins. I thought > maybe it was ESD - even though I'm working on a grounded mat with a groun= > iron. Are they particularly sensitive??
> > Data sheet:http://www.vishay.com/docs/72269/72269.pdf The faster and smaller the MOSFET the more static sensitive it will be but I don't think that that is your problem. Try putting your DVM on both AC and DC between various "ground" connections on your bench. Any reading over 0.1V is cause for concern. >
> cheers. > D. | |||||||||||||||||||||||||||||||
|
Posted by Archimedes' Lever on August 12, 2008, 7:55 pm
Please log in for more thread options
wrote: >> I'm having some probs repairing some gear with Si9410BDY SO-8 pkg mosfets in
>> them. >> >> The FET will appear to be faulty - replaced it - still no go......replace it >> again - it works - WTF! >> >> It's happened too many times to be finger trouble or gremlins. I thought >> maybe it was ESD - even though I'm working on a grounded mat with a grounded >> iron. Are they particularly sensitive?? >> >> Data sheet:http://www.vishay.com/docs/72269/72269.pdf >
>The faster and smaller the MOSFET the more static sensitive it will be >but I don't think that that is your problem. > >Try putting your DVM on both AC and DC between various "ground" >connections on your bench. Any reading over 0.1V is cause for >concern. > > >>
The very word MOSFET alone should say to anyone in the industry "very ESD susceptible". Remember folks, it boils down to the potential required to breach a single pn junction. These features are pretty damned small. ESD is now, has been for decades, and should be, a major part of the electronics industry, and I find it ludicrous that some engineers downplay susceptibilities. I have seen the micrographs.. parts that didn't even fail... right away. It looked like an Iraqi roadway. Proper ESD workstations and handling procedures should always be followed... as a rule... not merely when handling known to be susceptible devices. Even fields can cause failures on parts that haven't been placed yet. Even non volatile parts can build up and keep a charge, and discharge into a susceptible part, so proper procedures should be used at all times to ensure that every step possible was taken to keep all parts at as close as can be to a net zero stored electrostatic charge. Such tiny stored charges can be all the energy it takes to kill a pin on a sensitive device. | |||||||||||||||||||||||||||||||
|
Posted by HarryD on August 12, 2008, 8:40 pm
Please log in for more thread options
> wrote:
> >>> I'm having some probs repairing some gear with Si9410BDY SO-8 pkg
>>> mosfets in >>> them. >>> >>> The FET will appear to be faulty - replaced it - still no >>> go......replace it >>> again - it works - WTF! >>> >>> It's happened too many times to be finger trouble or gremlins. I thought >>> maybe it was ESD - even though I'm working on a grounded mat with a >>> grounded >>> iron. Are they particularly sensitive?? >>> >>> Data sheet:http://www.vishay.com/docs/72269/72269.pdf >>
>>The faster and smaller the MOSFET the more static sensitive it will be >>but I don't think that that is your problem. >> >>Try putting your DVM on both AC and DC between various "ground" >>connections on your bench. Any reading over 0.1V is cause for >>concern. >> >> >>>
>
> > The very word MOSFET alone should say to anyone in the industry "very > ESD susceptible". Remember folks, it boils down to the potential > required to breach a single pn junction. These features are pretty > damned small. > > ESD is now, has been for decades, and should be, a major part of the > electronics industry, and I find it ludicrous that some engineers > downplay susceptibilities. I have seen the micrographs.. parts that > didn't even fail... right away. It looked like an Iraqi roadway. > > Proper ESD workstations and handling procedures should always be > followed... as a rule... not merely when handling known to be > susceptible devices. Even fields can cause failures on parts that haven't > been placed yet. Even non volatile parts can build up and keep a charge, > and discharge into a susceptible part, so proper procedures should be > used at all times to ensure that every step possible was taken to keep > all parts at as close as can be to a net zero stored electrostatic > charge. > > Such tiny stored charges can be all the energy it takes to kill a pin on > a sensitive device. Hey Arch, your living in the dark ages, BGW. You are correct about some MOSFET devices will blow if you just get near them, especially if they have unprotected inputs. The gate on a MOSFET is the most sensitive pin and on these larger devices they look like 10nF to the other nodes. They are rated at +/-20V but can withstand >40V. So your 100pF body must be charged to >3KV
to blow the junction. The OP sounds very careful so I am betting, like most
others that ESD is not the problem. Cheers, Harry | |||||||||||||||||||||||||||||||
|
Posted by Archimedes' Lever on August 12, 2008, 9:55 pm
Please log in for more thread options
>
>> wrote:
>> >>>> I'm having some probs repairing some gear with Si9410BDY SO-8 pkg
>>>> mosfets in >>>> them. >>>> >>>> The FET will appear to be faulty - replaced it - still no >>>> go......replace it >>>> again - it works - WTF! >>>> >>>> It's happened too many times to be finger trouble or gremlins. I thought >>>> maybe it was ESD - even though I'm working on a grounded mat with a >>>> grounded >>>> iron. Are they particularly sensitive?? >>>> >>>> Data sheet:http://www.vishay.com/docs/72269/72269.pdf >>> >>>The faster and smaller the MOSFET the more static sensitive it will be >>>but I don't think that that is your problem. >>> >>>Try putting your DVM on both AC and DC between various "ground" >>>connections on your bench. Any reading over 0.1V is cause for >>>concern. >>> >>> >>>> >>
>> >> The very word MOSFET alone should say to anyone in the industry "very >> ESD susceptible". Remember folks, it boils down to the potential >> required to breach a single pn junction. These features are pretty >> damned small. >> >> ESD is now, has been for decades, and should be, a major part of the >> electronics industry, and I find it ludicrous that some engineers >> downplay susceptibilities. I have seen the micrographs.. parts that >> didn't even fail... right away. It looked like an Iraqi roadway. >> >> Proper ESD workstations and handling procedures should always be >> followed... as a rule... not merely when handling known to be >> susceptible devices. Even fields can cause failures on parts that haven't >> been placed yet. Even non volatile parts can build up and keep a charge, >> and discharge into a susceptible part, so proper procedures should be >> used at all times to ensure that every step possible was taken to keep >> all parts at as close as can be to a net zero stored electrostatic >> charge. >> >> Such tiny stored charges can be all the energy it takes to kill a pin on >> a sensitive device. >
> Hey Arch, your living in the dark ages, BGW. You are correct about some >MOSFET devices will blow if you just get near them, especially if they have >unprotected inputs. The gate on a MOSFET is the most sensitive pin and on >these larger devices they look like 10nF to the other nodes. They are rated >at +/-20V but can withstand >40V. So your 100pF body must be charged to >3KV >to blow the junction. The OP sounds very careful so I am betting, like most >others that ESD is not the problem. > Cheers, > > Harry > > "your"? "BGW"? Bwuahahahahah! As little as 20V electrostatic charge on a person can blow just about any modern chip made these days. 3kV WILL blow anything. The chip makers that tout resistance to such voltages refer to parts IN CIRCUIT, wired in a specific manner. This discussion is about raw parts, as assemblies are being populated, etc. Even a "High Voltage Diode" is actually a STACK of pn junctions. A single one of those pn pairs would be susceptible. Being in a stack is what makes it an HV Diode. In a chip, however, the features are very, very tiny and very, very frail. Far more so than they were back at the advent of CMOS and ESD concerns. Also, before an FET goes in, especially with a high sensitivity device, merely touching the pins with fingers, grounded or not, and solder iron tips can blow them. If his iron is not a modern, ESD compliant type, there is no way to know if it is grounded at the tip or carrying a floating AC potential. If he grounds the tip, is he also incorporating the 1 MegOhm series limiter? We had some transducers that were FET included that had the leads wired together for handling prior to installation, and installation required a specific procedure. Yes, many blew before we decided that indeed, it IS a concern. | |||||||||||||||||||||||||||||||
