[SI-LIST] Re: variations in ESD simulators
- From: Ram Chundru <rchundru_umr@xxxxxxxxx>
- To: Douglas Smith <doug@xxxxxxxxxx>, emc-pstc <emc-pstc@xxxxxxxx>, Si-List <si-list@xxxxxxxxxxxxx>
- Date: Thu, 9 Dec 2010 17:46:25 -0800 (PST)
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 <doug@xxxxxxxxxx>
To: emc-pstc <emc-pstc@xxxxxxxx>; Si-List <si-list@xxxxxxxxxxxxx>
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: doug@xxxxxxxxxx[2] \ _ / ] \ _ / Web:
http://www.dsmith.org[3]
--------------------------------------------------------------
--- Links ---
1 http://emcesd.com/tt2010/tt120210.htm
2 mailto:doug@xxxxxxxxxx
3 http://www.dsmith.org
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List technical documents are available at:
http://www.si-list.net
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List technical documents are available at:
http://www.si-list.net
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
