RE: Probing power plane with analyser
Thankyou to all those who responded to my probing question. My initial response to the engineer was to try and characterise the board using near field probes however he is intent on looking directly at the 3v power rail. Given this, my primary concern is with protecting the analyser. Since his frequencies of interest extend to 300MHz, the LISN is not much of an option. The testing will initially only involve A:B comparisons so I feel satisfied that it should be safe enough to proceed with the DC blocking capacitor method. Regards, Cameron O'Phee. EMC Safety Precompliance. Aristocrat Technologies Australia. Telephone : +61 2 9697 4420 Facsimile : +61 2 9663 1412 Mobile : 0418 464 016 --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Probing power plane with analyser.
Yes, Not only will the LISN have poor performance above 100 MHz, but the CISPR voltage probe or a down and dirty series capacitance will have trouble at these frequencies, although they will all work well at lower frequencies. Many of the other suggestions from members on this subject can be used to measure higher frequencies. As is invariably the case in this business, the correct answer depends on the frequency range of concern and the problem actually trying to be identified. Usually for the higher frequencies I use field probes along the board or cables rather than contact, sometimes adding short wires as intentional unintentional radiators. Paul McCoy chasgra...@aol.com@ieee.org on 09/29/2000 02:17:49 PM Please respond to chasgra...@aol.com Sent by: owner-emc-p...@ieee.org To: pwmc...@ra.rockwell.com, O'p...@ali.com.au cc: emc-p...@majordomo.ieee.org, seif...@ali.com.au Subject: Re: Probing power plane with analyser. Hi there - The AC LISN will have a very poor performance above about 100MHz don't you think?? --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Probing power plane with analyser.
Hi there - The AC LISN will have a very poor performance above about 100MHz don't you think?? --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Probing power plane with analyser.
We made a probe using rigid coax with its built in SMA connector. Solder a pin to the side of the coax and file it diagonally to create a sharp point. To increase the loading impedance we used an SMA collar that had been filed out to place a series chip resistor of 470 ohms in series with the center conductor. Then we calibrated the probe for insertion loss up to 2 GHz and could probe around on the board. If I had it to do again, I would move the resistor out very close to the probe tip to reduce the effects of the series inductance, but what worked worked, so we went on. - Robert - -Original Message- From: pwmc...@ra.rockwell.com pwmc...@ra.rockwell.com To: Cameron O'phee O'p...@ali.com.au Cc: 'EMC - PSTC Forum' emc-p...@majordomo.ieee.org; Roman Seifert seif...@ali.com.au List-Post: emc-pstc@listserv.ieee.org Date: Thursday, September 28, 2000 5:50 AM Subject: Re: Probing power plane with analyser. Cameron, If you are looking for a measure of the conducted RF coming off the board the standard AC LISN works for DC power as well. The voltage probe per CISPR 16 will also work and gives a standardized impedance that can be probed from point to point (or if you are looking for a down and dirty measurement just put a capacitor in series with your probe to block the DC). Paul McCoy Cameron O'phee O'p...@ali.com.au@ieee.org on 09/27/2000 07:59:24 PM Please respond to Cameron O'phee O'p...@ali.com.au Sent by: owner-emc-p...@ieee.org To: 'EMC - PSTC Forum' emc-p...@majordomo.ieee.org cc: Roman Seifert seif...@ali.com.au Subject: Probing power plane with analyser. Hello All, I have been asked by one of our design engineers if I can measure the RF signature on the 3v plane on one of our PCB designs. The purpose of this is to compare it to proposed changes for cost reduction, ie removal of bypass caps. I would assume I need some sort of CDN but I have no designs for this application. Does anyone have any ideas on how I can safely probe a 3v DC power rail with an EMC analyser (HP8591E)? Regards, Cameron O'Phee. EMC Safety Precompliance. Aristocrat Technologies Australia. Telephone : +61 2 9697 4420 Facsimile : +61 2 9663 1412 Mobile : 0418 464 016 --- --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Probing power plane with analyser.
Cameron, Checkout Doug Smith's webpage for some insight on making RF measurements using various (homemade) probes. http://emcesd.com/ Good Luck, George -Original Message- From: Cameron O'phee [mailto:O'p...@ali.com.au] Sent: Wednesday, September 27, 2000 8:59 PM To: 'EMC - PSTC Forum' Cc: Roman Seifert Subject: Probing power plane with analyser. Hello All, I have been asked by one of our design engineers if I can measure the RF signature on the 3v plane on one of our PCB designs. The purpose of this is to compare it to proposed changes for cost reduction, ie removal of bypass caps. I would assume I need some sort of CDN but I have no designs for this application. Does anyone have any ideas on how I can safely probe a 3v DC power rail with an EMC analyser (HP8591E)? Regards, Cameron O'Phee. EMC Safety Precompliance. Aristocrat Technologies Australia. Telephone : +61 2 9697 4420 Facsimile : +61 2 9663 1412 Mobile : 0418 464 016 --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Probing power plane with analyser.
Cameron, If you are looking for a measure of the conducted RF coming off the board the standard AC LISN works for DC power as well. The voltage probe per CISPR 16 will also work and gives a standardized impedance that can be probed from point to point (or if you are looking for a down and dirty measurement just put a capacitor in series with your probe to block the DC). Paul McCoy Cameron O'phee O'p...@ali.com.au@ieee.org on 09/27/2000 07:59:24 PM Please respond to Cameron O'phee O'p...@ali.com.au Sent by: owner-emc-p...@ieee.org To: 'EMC - PSTC Forum' emc-p...@majordomo.ieee.org cc: Roman Seifert seif...@ali.com.au Subject: Probing power plane with analyser. Hello All, I have been asked by one of our design engineers if I can measure the RF signature on the 3v plane on one of our PCB designs. The purpose of this is to compare it to proposed changes for cost reduction, ie removal of bypass caps. I would assume I need some sort of CDN but I have no designs for this application. Does anyone have any ideas on how I can safely probe a 3v DC power rail with an EMC analyser (HP8591E)? Regards, Cameron O'Phee. EMC Safety Precompliance. Aristocrat Technologies Australia. Telephone : +61 2 9697 4420 Facsimile : +61 2 9663 1412 Mobile : 0418 464 016 --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Probing power plane with analyser.
Hello All, I have been asked by one of our design engineers if I can measure the RF signature on the 3v plane on one of our PCB designs. The purpose of this is to compare it to proposed changes for cost reduction, ie removal of bypass caps. I would assume I need some sort of CDN but I have no designs for this application. Does anyone have any ideas on how I can safely probe a 3v DC power rail with an EMC analyser (HP8591E)? Regards, Cameron O'Phee. EMC Safety Precompliance. Aristocrat Technologies Australia. Telephone : +61 2 9697 4420 Facsimile : +61 2 9663 1412 Mobile : 0418 464 016 --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Probing power plane with analyser.
Cameron: That's fairly easy to do as long as you: 1. Take all measurments from the same reference points before and after the changes and 2. Use a DC block on the input to the analyzer ;other wise you may have an expensive input to replace. Most analyzers inputs are not protected for DC. Most companies sell the DC isolator as an accessory. Ralph Cameron EMC Consultant and Suppression of Consumer Electronic Equipment. - Original Message - From: Cameron O'phee O'p...@ali.com.au To: 'EMC - PSTC Forum' emc-p...@majordomo.ieee.org Cc: Roman Seifert seif...@ali.com.au Sent: Wednesday, September 27, 2000 8:59 PM Subject: Probing power plane with analyser. Hello All, I have been asked by one of our design engineers if I can measure the RF signature on the 3v plane on one of our PCB designs. The purpose of this is to compare it to proposed changes for cost reduction, ie removal of bypass caps. I would assume I need some sort of CDN but I have no designs for this application. Does anyone have any ideas on how I can safely probe a 3v DC power rail with an EMC analyser (HP8591E)? Regards, Cameron O'Phee. EMC Safety Precompliance. Aristocrat Technologies Australia. Telephone : +61 2 9697 4420 Facsimile : +61 2 9663 1412 Mobile : 0418 464 016 --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
