Application of ESD to connector pins has always been a point of
contention. I have usually exempted them from testing. My basis is
that the only authority I recall on the subject exempted connector pins.
The authority was the withdrawn CENELEC 101? series of immunity documents
which preceeded the current generic standards.
Recently a new work item proposal 77B/189/NP Amendment to IEC 61000-4-2 -
"Definition of accessable parts under normal operating conditions" was
distributed for comment to the TC77B committee. As mentioned it's a NWIP
and has a long way to go to become a published ammendment. Nonetheless,
it appears to be a well constructed rationale for exempting many connector
pins from discharge. I have adopted this guidance at Curtis-Straus.
Some examples of the text:
... the following exclusions apply:
the points or surfaces of equipment which are no longer accessible after
installation
the contacts of coaxial and multipin connectors which are provided with a
metallic shell. Note: contacts within a plastic shell shall be subject to
air discharge testing only.
those contacts of connectors or other accessible parts which are ESD
sensitive because of functional reasons and are provided with an ESD
warning label...
the points and surfaces which are only present under customer service
and are considered rarely accessed, eg changing batteries etc.
Anyone who wants a copy of this one page document should send me their
name and fax number.
Jon D. Curtis, PE
Curtis-Straus LLC [email protected]
Laboratory for EMC, Safety, NEBS, SEMI-S2 and Telecom
527 Great Road voice (978) 486-8880
Littleton, MA 01460 fax (978) 486-8828
http://www.curtis-straus.com
On Wed, 22 Jul 1998 [email protected] wrote:
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> From: Jim To <[email protected]>
> Organization: Force Computers, Inc.
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> Thank you for your comments. It appears that the standard does not specify
> the application of ESD to the rear I/O ports of a unit. However, if there
> are front I/O ports, then ESD is required on the exposed metal parts. I/O
> ports provided at the front panel do not always get connected to
> interconnecting cables. Would you have to consider a worse scenario by
> assuming that cables are not connected?
>
> Has anyone have the experience, good or bad, on conducting ESD directly to
> the exposed pins of I/O ports? Many thanks.
>
> Jim To
> Force Computers, Inc.
>
>
> Matejic, Mirko wrote:
>
> > Jim,
> >
> > All user accessible areas should be tested to ESD immunity.
> >
> > However, with test setup having RS232 connector terminated
> > with a cable, I/O connector pins would not be accessible. RS232
> > connector shell will be accessible and should be tested as such.
> >
> > Mirko Matejic
> >
>
