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 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
