RE: Zero Crossing Question
I agree with Scott's take on this, and I can vouch for the experiences others have cited where a seemingly suitable alternative has in reality proved otherwise. I have seen this with both semiconductors (opto isolators) and passives (VSD DC link capacitors and ferrites). If the datasheets are *identical*, then I say use the parts that work and put the question to On semi why their part behaves differently. Regards - Chris -Original Message- From: Scott Lacey [SMTP:sco...@world.std.com] Sent: Monday, January 21, 2002 4:47 PM To: Bouse, John Cc: emc-p...@majordomo.ieee.org Subject:RE: Zero Crossing Question Zero Crossing QuestionJohn, I think you already have the answer to the problem. You stated that Harris or Intersil IC's work properly regardless of the mains polarity. Some years back I had an issue where another manufacturer's replacement was substituted for a Sprague ULN2003 Darlington Array that I had specified in a design. I was using the ULN2003 to buffer a reset pulse distributed in a system. The other brand was not capable of switching quickly enough in this application. Replacing the ICs with the specified part solved the problem. I would not waste valuable engineering time resolving an issue that only occurs with one vendor's part. Just one man's opinion, Scott Lacey Simplicate, don't complicate! -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Bouse, John Sent: Monday, January 21, 2002 9:20 AM To: emc-p...@majordomo.ieee.org Subject: Zero Crossing Question Hi Group, Our manufacturing personnel encountered a strange problem: when the mains plug used on a 230V/50Hz equipment that has an internal zero crossing reference integrated circuit (specifically, a CA3059) is reversed (this can occur in countries such as Germany, Italy, France and Switzerland), the zero crossing pulses appear with a 20 millisecond spacing, rather than the expected 10 millisecond spacing. Harris or Intersil IC's work properly regardless of the mains polarity. ON Semiconductor IC's appear to be polarity sensitive. They will produce the proper number of pulses with only one mains polarity. The incorrect spacing of these zero crossing pulses affects the normal operation of the equipment. Has anyone encountered and, hopefully, solved this problem? Regards, John Bouse PKI This e-mail has been scanned for all viruses by Star Internet. The service is powered by MessageLabs. For more information on a proactive anti-virus service working around the clock, around the globe, visit: http://www.star.net.uk File: ATT2.htm This e-mail has been scanned for all viruses by Star Internet. The service is powered by MessageLabs. For more information on a proactive anti-virus service working around the clock, around the globe, visit: http://www.star.net.uk --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: Zero Crossing Question
John, Or another example where different companies' equivalent parts are not equivalent-- this is one that I ran into in 1977. I had designed a Power-On-Reset (POR) circuit using a 555 timer, and had tested the circuit on a solderless breadboard. I was being sneaky in my design, and used the RESET, TRIGGER, and THRESHOLD inputs as three separate inputs to the 555. When we built the first tester the POR circuit didn't work. I then discovered that there were two flavors of 555 timers-- TI's and most companies 555's obeyed TRIGGER if(TRIGGER 1/3*VCC) AND (THRESHOLD 2/3*VCC). But the National Semiconductor LM555, which we used when we built the tester, obeyed THRESHOLD instead... Since this is an undefined input state for the 555, the chip designers did as they pleased. I have heard of many other cases where engineers have used components outside the published specifications, and gotten burned for their trouble. Bob Pease has written several Pease Porridge columns in Electronic Design about specmanship, and about how Design Engineers and Applications Engineers at chip manufacturers *try* to write honest datasheets over the objections of the marketeers. His best advice was: 1. If in doubt, try it out. 2. If an unspecified characteristic is important to you, contact the manufacturer and get them to guarantee it in writing. You may find yourself having to retest your design every time the chip manufacturer does a die shrink or moves the chip to a different process or plant. But you are much better off to find this out early, and have time to find a suitable alternative part or make a lifetime buy of the older (working) part than to suddenly have 100% of your products fail in production. John Barnes Advisory Engineer Lexmark International (soon to be Chief Engineer, dBi Corporation) --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: Zero Crossing Question
Hi Folks Could this ON Semiconductors problem be something to do with: a) The fact that the neutral is generally not at ground potential, but has floated up due the current flowing in it? or b) The actual PSU has a filtering arrangement that is non-symmetrical wrt true ground? (Often evidenced by the leakage current differing when Line and Neutral are reversed) John Allen -Original Message- From: Bouse, John [mailto:john.bo...@perkinelmer.com] Sent: 21 January 2002 14:20 To: emc-p...@majordomo.ieee.org Subject: Zero Crossing Question Hi Group, Our manufacturing personnel encountered a strange problem: when the mains plug used on a 230V/50Hz equipment that has an internal zero crossing reference integrated circuit (specifically, a CA3059) is reversed (this can occur in countries such as Germany, Italy, France and Switzerland), the zero crossing pulses appear with a 20 millisecond spacing, rather than the expected 10 millisecond spacing. Harris or Intersil IC's work properly regardless of the mains polarity. ON Semiconductor IC's appear to be polarity sensitive. They will produce the proper number of pulses with only one mains polarity. The incorrect spacing of these zero crossing pulses affects the normal operation of the equipment. Has anyone encountered and, hopefully, solved this problem? Regards, John Bouse PKI --- 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: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: Zero Crossing Question
Zero Crossing QuestionJohn, I think you already have the answer to the problem. You stated that Harris or Intersil IC's work properly regardless of the mains polarity. Some years back I had an issue where another manufacturer's replacement was substituted for a Sprague ULN2003 Darlington Array that I had specified in a design. I was using the ULN2003 to buffer a reset pulse distributed in a system. The other brand was not capable of switching quickly enough in this application. Replacing the ICs with the specified part solved the problem. I would not waste valuable engineering time resolving an issue that only occurs with one vendor's part. Just one man's opinion, Scott Lacey Simplicate, don't complicate! -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Bouse, John Sent: Monday, January 21, 2002 9:20 AM To: emc-p...@majordomo.ieee.org Subject: Zero Crossing Question Hi Group, Our manufacturing personnel encountered a strange problem: when the mains plug used on a 230V/50Hz equipment that has an internal zero crossing reference integrated circuit (specifically, a CA3059) is reversed (this can occur in countries such as Germany, Italy, France and Switzerland), the zero crossing pulses appear with a 20 millisecond spacing, rather than the expected 10 millisecond spacing. Harris or Intersil IC's work properly regardless of the mains polarity. ON Semiconductor IC's appear to be polarity sensitive. They will produce the proper number of pulses with only one mains polarity. The incorrect spacing of these zero crossing pulses affects the normal operation of the equipment. Has anyone encountered and, hopefully, solved this problem? Regards, John Bouse PKI
