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Electronics => Projects, Designs, and Technical Stuff => Topic started by: MrMetthew on April 25, 2018, 03:50:55 pm

Title: ESD safe caps in series still ESD safe?
Post by: MrMetthew on April 25, 2018, 03:50:55 pm
Hi all,

I was wondering, if I put two esd safe capacitors (e.g. AVX ESD55C472K4T2A-18) in series to double the voltage rating of the cap, will they preserve their esd safe properties?
Title: Re: ESD safe caps in series still ESD safe?
Post by: T3sl4co1l on April 25, 2018, 05:51:35 pm
I don't see why not.

Tim
Title: Re: ESD safe caps in series still ESD safe?
Post by: MrMetthew on April 26, 2018, 07:53:50 am
Quote from: T3sl4co1l on April 25, 2018, 05:51:35 pm
I don't see why not.

Tim

Maybe because the esr gets doubled? I am not sure..
Title: Re: ESD safe caps in series still ESD safe?
Post by: jmelson on April 26, 2018, 07:41:12 pm
Quote from: MrMetthew on April 25, 2018, 03:50:55 pm
Hi all,

I was wondering, if I put two esd safe capacitors (e.g. AVX ESD55C472K4T2A-18) in series to double the voltage rating of the cap, will they preserve their esd safe properties?
That's 4700 pF?  Geez, what's this ESD safe stuff?  I think it would be VERY hard to damage a 4700 pF cap unless your ESD conditions are so bad you are getting visible/audible sparks jumping around.  The really worst-case human body model has a 470 pF reservoir cap that is charged to the test voltage, this is worse than almost any real ESD event you can imagine in a station where exposed PC boards are handled.

Jon
Title: Re: ESD safe caps in series still ESD safe?
Post by: Niklas on April 26, 2018, 09:33:00 pm
The internal structure is slightly different on these capacitors to provide a discharge path that bypasses the wanted capacitance. Apart from that they are just like normal capacitors and can be connected in series or in parallell.

https://incompliancemag.com/article/effectiveness-of-multilayer-ceramic-capacitors-for-electrostatic-discharge-protection/
Title: Re: ESD safe caps in series still ESD safe?
Post by: wraper on April 26, 2018, 10:07:09 pm
Quote from: Niklas on April 26, 2018, 09:33:00 pm
The internal structure is slightly different on these capacitors to provide a discharge path that bypasses the wanted capacitance. Apart from that they are just like normal capacitors and can be connected in series or in parallell.

https://incompliancemag.com/article/effectiveness-of-multilayer-ceramic-capacitors-for-electrostatic-discharge-protection/
They don't provide any discharge path. The difference is in placement of conductive plates.