REGISTER | LOGIN
Home    Bloggers    Blogs    Article Archives    Messages    About Us   
Tw  |  Fb  |  In  |  Rss
Tim Micun

The Shocking Truth About Static Discharge Dangers

Tim Micun
webbpatj
webbpatj
11/3/2015 9:29:35 AM
User Rank
Newbie
ESD
Just because the electronics didn't fail right away, it doesn't mean that the MTBF (Mean Time Between Failure) of the circuit hasn't been decreased drastically.

50%
50%
Hughston
Hughston
2/5/2015 2:17:00 AM
User Rank
Newbie
Re: More ESD comments
Let me clarify my earlier comment.  I have not seen traces burned off the board by ESD strikes.  But, you will often see burn marks on the solder mask where the ESD jumped between traces or components on the board.  If you can turn off the lights in the test room you can often watch the ESD spark to see the path it takes in your design.

50%
50%
Vishal Prajapati
Vishal Prajapati
1/16/2015 1:01:35 AM
User Rank
Master
Re: More ESD comments
Hughston, I have seen the failure of the electronics components using ESD by at max malfunctioning of them or slight heating when run normally.

 

But have never seen such an extreme case when the tracks are burnt. It is nice to know that you have pointed out the true situation which can be a result of ESD.

 

And ya, I had never thought, how thoughtfull design is the USB connetor which has I/O pins shorter than the actual connector length, so the user will not accidently touch them.

50%
50%
TimLittelfuse
TimLittelfuse
1/13/2015 9:11:16 AM
User Rank
Newbie
Re: More ESD comments
Great, real life observations, 

50%
50%
TimLittelfuse
TimLittelfuse
1/13/2015 9:10:18 AM
User Rank
Newbie
Re: Fear of All Failure Cases
My opinion, with proper design methodology, you can reduce, but not eliminate ESD risk.  Environment is biggest component in the ESD link, and we have great difficulty controlling it.

 

50%
50%
Vishal Prajapati
Vishal Prajapati
1/13/2015 6:16:49 AM
User Rank
Master
ESD a secrete villain
I have worked on one of the design of water dispensor which was solar and battery powered. It had the GSM modem which would be connected to MCU via serial communication. In between there was a MACX232 IC which was the main component to get failed in most of the outages.

 

Due to no reason the MAX232 will stop responding. We later figured out that the chinise make was cheaper but unreliable which caused most of the failure due to ESD. Later on we replaced it with TI original ICs and problem got solved. Then after very few cases of ESD failure.

50%
50%
fasmicro
fasmicro
1/10/2015 12:07:44 PM
User Rank
Master
Re: Fear of All Failure Cases
>> Engineer might minimize the use of extra protection component as much as possible.

That is coming from experience I guess. You do not need a lot of protection to make protection circuit. And the simpler the protection, the better.

50%
50%
Hughston
Hughston
1/10/2015 3:07:28 AM
User Rank
Newbie
More ESD comments
My original comments were as long as the article but I'll tone it down.

The first thing I would do to prevent ESD failures is to give the product a lot of insulation resistance. If the ESD can't strike, it is less likely to cause a failure.

Design the product well from an EMI standpoint. An ESD strike near the product can cause damage or upset. This type of immunity is sometimes tested by striking a vertical or horizontal plate near the product.

A USB or power input needs a more robust protection because they have power transients and ESD.

If there are outside connections like power, phone lines or USB that are connected during use, you can get more current in the ESD strike. An unconnected handheld device does not get a high current strike, but connect it to a charger and it gets more current.

Something like a wall wart has high insulation resistance during the first ESD strikes but the insulation gets punched through over time by the strikes. Wall warts and other parts can wear out over time with ESD and you need to start over with a fresh product if you observe the ESD immunity going down.

If ESD gets into your design it can jump around. You might see the burn tracks or just turn off the room lights and see where it goes.

There is a lightning rod effect with ESD. Lightning likes pointy metal and so does ESD. The pointy metal can be a component lead, switch, trace or connector lead.

50%
50%
DaeJ
DaeJ
1/8/2015 2:35:23 PM
User Rank
Master
Fear of All Failure Cases
All possible failure case could be simply protected in the protection circuit.  I never see any huge catastrophic failures in the development staging circuit. Engineer might minimize the use of extra protection component as much as possible. A proper protection circuit does not always require the protection component. Two topics might be separated in some cases.  

50%
50%
More Blogs from Tim Micun
This live chat session will discuss circuit protection solutions for ESD. This is the second of three tech briefs before the Ask the Experts session.
flash poll
educational resources
 
follow Planet Analog on Twitter
Planet Analog Twitter Feed
like us on facebook
our partners
Planet Analog
About Us     Contact Us     Help     Register     Twitter     Facebook     RSS