But for air discharge, one is supposed to approach the victim, err, UUT, at
1m/sec, so proximity, not pulling the trigger, initiates the discharge.
Cortland
KA5S
----- Original Message -----
From: Bill Owsley <mailto:[email protected]>
To: Douglas Smith <mailto:[email protected]> ;emc-pstc
<mailto:[email protected]> ;Si-List <mailto:[email protected]> ;Ram
Chundru <mailto:[email protected]>
Sent: 12/10/2010 1:28:13 AM
Subject: Re: [SI-LIST] variations in ESD simulators
We have an ESD gun that for air discharge, when the trigger is pulled, will
broadcast a field that is known to us to cause most of our anomalies. Same
happens when the trigger is released after the actual air discharge to the
intended target. We have a name for this gun, but decency, what little I
have, keep me from repeating it ... ps. two cal labs and the manufacturer,
even when told what to look for and how to see it, say it is just fine, no
problems, it works as intended. So it appears that outside of the defined
performance, any performance is allowed ?!?!?!
Bill
In the event of a national emergency,
click on the following links to provide directions to your duly elected
mis-representatives.
http://www.usa.gov/Contact/Elected.shtml
or...
https://writerep.house.gov/writerep/welcome.shtml
http://www.senate.gov/general/contact_information/senators_cfm.cfm
if really desperate...
http://www.usa.gov/Contact/Elected.shtml
--- On Thu, 12/9/10, Ram Chundru <[email protected]> wrote:
From: Ram Chundru <[email protected]>
Subject: Re: [SI-LIST] variations in ESD simulators
To: "Douglas Smith" <[email protected]>, "emc-pstc" <[email protected]>,
"Si-List" <[email protected]>
Date: Thursday, December 9, 2010, 8:46 PM
Hi Doug,
The IEC 61000-4-2 standard is a loosely defined spec. It only specifies
a few
parameters for the discharge current and with pretty big tolerances (peak
current has +/-10% tolerance, rise time has a range from 0.7 ns - 1 ns and
current at 30 ns and 60 ns have +/-30% tolerance). Consequently it is possible
for all the commercially available ESD generators to meet the specifications
but still produce vastly different discharge current pulses. For example, one
generator might produce a slowly falling first hump and another generator
might produce a rapidly falling first hump as the fall time is not specified
in the standard. This results in big differences in current derivatives (didt)
which in turn results in big differences in the fields coupled by the two ESD
generators to the EUT.
The standard does not specify the transient fields generated by the ESD
generators which are a combination of fields caused by the discharge current
at the tip of the generators and the fields caused by the faster currents
inside the ESD gun bodies. This variation in fields among ESD generators is a
bigger contributor to the un-reproducibility of test results (soft failures)
than the variations in the discharge currents (hard failures) since the
current is somewhat regulated by the spec but not the fields.
Thanks,
Ram
EMC Engineer
Apple Inc.
________________________________
From: Douglas Smith <[email protected]>
To: emc-pstc <[email protected]>; Si-List <[email protected]>
Sent: Wed, December 8, 2010 9:45:25 PM
Subject: [SI-LIST] variations in ESD simulators
Hi All,
My latest monthly article is out!
Technical Tidbit - December 2010
Comparing "IEC 61000-4-2 Compliant" ESD Simulators
Abstract: IEC 61000-4-2 compliant ESD Simulators (150 pF/330 Ohm
network)
arerequired to meet a specified waveform. Results are presented here
comparing the current waveforms delivered into a metal tabletop
(Horizontal
Coupling Plane of IEC 61000-4-2) by three different simulators. The
results
were not as uniform as expected. The data presented has implications
for the
reproducibility of ESD testing.
The link to the article is: http://emcesd.com/tt2010/tt120210.htm[1]
Doug
-- -------------------------------------------------------------- ___ _
Doug
Smith \ / ) P.O. Box 1457 ========= Los Gatos, CA 95031-1457 _ / \ / \ _
TEL/FAX: 408-356-4186/358-3799 / /\ \ ] / /\ \ Mobile: 408-858-4528 |
q-----() | o | Email: [email protected][2] \ _ / ] \ _ / Web:
http://www.dsmith.org[3]
--------------------------------------------------------------
--- Links ---
1 http://emcesd.com/tt2010/tt120210.htm
2 mailto:[email protected]
3 http://www.dsmith.org
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