Dave: I would be delighted to take a target (on loan) and do my best to evaluate it ... within the limitations of my instrumentation.
Thanks for the offer. Jim Ericson Acme Testing Company [email protected] ----- Original Message ----- From: "drcuthbert" <[email protected]> To: "'Jim Ericson'" <[email protected]>; "emcpost" <[email protected]> Cc: "drcuthbert" <[email protected]> Sent: Monday, May 05, 2003 7:45 AM Subject: ESD Gun targets > Jim, > > the Pelligrini Target spec in EN61000-4-2 is quite a challenge to meet. The 1 dB insertion loss delta from DC to 4 GHz to be exact. The simulation of my proposed PCB design shows that it can meet the spec and I have the equipment to verify this. > > I will build a few targets. Perhaps a few of you would like a target to use and to provide feedback. Who wants a target? Step right up and get your red hot Pelligrini targets! > > Dave Cuthbert > Micron Technology > > -----Original Message----- > From: Jim Ericson [mailto:[email protected]] > Sent: Saturday, May 03, 2003 5:09 PM > To: emcpost > Cc: drcuthbert > Subject: Re: ESD Gun "verification" > > > Dave: > > Yes. The current-sensing transducer that I built ("Pelligrini Target") is > per the Annex B drawings in EN 61000-4-2:1995 + A1:1998 +A2:2001. It has > five paralleled 240 Ohm resistors arranged radially around the oscilloscope > side to give 48 Ohms. On the ESD Gun side are twenty-five radially spaced > 50 Ohm resistors to give 2 Ohms. Transconductance is 1 Amp/1 Volt into 50 > Ohms. > > The present Standard requires a minimum 1 GHz bandwidth oscilloscope. > > I use a Pasternak Model PE7002-30 (DC to 2 GHz) 1 Watt Attenuator between > the Pelligrini Target and the scope (voltage ratio of 32). The oscilloscope > is a Tektronix 7104 with 7B10 time base, and a 7A26 dual-trace amplifier. > > I'll email a couple of photos to you (offline), and copy Mr. Pommerenke and > Mr. Kinney. > > Regards, > Jim Ericson > Acme Testing Company > [email protected] > > > ----- Original Message ----- > From: "drcuthbert" <[email protected]> > To: "'Jim Ericson'" <[email protected]> > Sent: Friday, May 02, 2003 8:07 AM > Subject: RE: ESD Gun "verification" > > > > Jim, > > > > I simulated this. I am assuming the circuit is a 2 ohm resistor to GND. If > so, the series inductance must be <0.1 nH for the 2 ohm resistor. Does this > sound right? I can do this with 25 paralleled 49.9 ohm resistors arranged > radially around the input (discharge) point. > > > > Dave Cuthbert > > Micron Technology > > > > -----Original Message----- > > From: Jim Ericson [mailto:[email protected]] > > Sent: Thursday, May 01, 2003 11:50 PM > > To: emcpost > > Subject: ESD Gun "verification" > > > > > > > > John: > > > > I faced the same problem about six years ago. I needed to do > "verification" > > in between the expensive annual "calibrations". I first explored the > option > > of buying a Pelligrini Target. As I recall, the quotes I received were > > around $2000. That seemed outrageous, so I decided to build one myself. > > I'll bet it took me at least 3 days to make sense of those goofy > mechanical > > drawings in 61000-4-2. If only they had included a photograph or good > > cross-section in the Standard! > > > > Anyway, I finally figured it out, translated the drawings into something > > understandable by a U.S. machine shop, and got all the brass parts > > fabricated locally. It took several in-process consulting sessions with > the > > machinist, but I finally got all the brass parts done for around $300. > > Then, I purchased a $25 silver electroplating kit. It was like Science > Fair > > time in my workshop! Some hours of painstaking soldering later, the > target > > was completed. I mounted it over a specially-drilled hole in the brass > wall > > panel of our anechoic chamber (you need a Faraday Cage of some sort, and > > this seemed the easiest). I did a quick check using our Tektronix 1 GHz > > analog oscilloscope ... and the risetimes and overall waveforms measured > > within spec! Then, I sent the target to Haefely-Trench for a > "calibration" > > (against their standard Pelligrini target). The results were very, very > > close. > > > > Having performed many verifications at this point, my advice (if you want > > fairly accurate and repeatable results): > > > > 1. Make (or buy) something resembling the 61000-4-2 target. > > 2. Use a Faraday Cage. > > 3. Be aware how important the POSITION of the ESD Gun Grounding Strap > is > > to these measurements ... especially to risetime measurements. I always > > take a photograph of the setup, including the "shape" of the Grounding > Strap > > and where it is attached. If you don't do this, you'll get pretty wild > > variability between verifications. > > 4. Even a 500 MHz oscilloscope would probably be OK for "verification". > > Just make certain that all setup parameters (including Ground Strap > > placement) are EXACTLY the same each time. That way, if the GUN happens > to > > change, you'll at least know what to do next. > > > > Give me a call if you'd like a photo. > > > > Good luck! > > > > Jim Ericson > > Quality System Manager/Sr. EMC Engineer > > Acme Testing Company > > Acme, WA. > > 888-226-3837 > > [email protected] > > > > ----- Original Message ----- > > From: "John Harrington" <[email protected]> > > To: <[email protected]> > > Sent: Thursday, May 01, 2003 11:45 AM > > Subject: ESD gun verification > > > > > > > > > > Hello All > > > > > > Does any one have a quick and dirty (and hopefully cheap) way to verify > > the > > > performance of an ESD gun. > > > > > > Please, no one suggest building the current sensing system described in > > the > > > back of IEC 61000-4-2. I don't understand the drawings let alone have > the > > > workshop or materials to consider it. Although, I may pay someone to > > build > > > it for me... > > > > > > I am desperate enough to consider buying something off the shelf (if I > > could > > > find said shelf). > > > > > > All help appreciated > > > > > > John Harrington > > > EMC Technical Manager > > > F-Squared Laboratories > This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
