For a First order Approximation, use the Charts in the IPC-2221 Fig 6-4 "Conductor thickness and width for internal and external layers". ..... Where the copper foil thickness in Fig 6-4. = plating thickness in the hole. the Conductor width in Fig 6-4. = hole dia. * pi (3.141) Example, Can a 13 mil hole with 1 mil copper plating carry one Amp? Conductor width is 13* 3.1 = 40 mil Conductor thickness is 1 mil Using Fig B (of Fig 6.4): Cross section in Sq. Mils = 30 (about that anyway) Using Fig C (of Fig 6.4) Internal conductors: An internal conductor of 30 Cross section in Sq. Mils will carry 1 amp and experience a 20 deg C temperature rise. Answer: A 13 mil hole with 1 mil copper plating will carry one Amp in most applications. For all the derating these charts have seen, this should give you a conservative answer. We use this approach to determine the number of laser vias needed to run power from one layer to the next. Using it, we have not had any problems. On the other hand, we have not made any measurements, so there is no supporting data. Just a warm feeling, ..... about 20 deg C. George Franck, CID who is hoping to be a CID++ -----Original Message----- From: Estrada, Roland [mailto:[log in to unmask]] Sent: Wednesday, October 10, 2001 11:30 AM To: [log in to unmask] Subject: Re: [TN] current carrying capacity of PTH Filled with the lead? Vias? Clad Copper thickness? Plated Copper thickness of the hole by Class 1, 2 or 3? Lots of questions to look at. I don't know of any charts. You could calculate this to a certain condition by the circumference of the nominal hole size, then by the thickness of the board. This would give you a flat pattern of this area (X and y) then use the standard IPC current charts from there. Roland Estrada CID Lockheed Martin - Dallas -----Original Message----- From: Geoff Layhe [mailto:[log in to unmask]] Sent: Wednesday, October 10, 2001 8:41 AM To: [log in to unmask] Subject: [TN] current carrying capacity of PTH Hi All, Does anyone have information such as formula, graphs etc regarding current carrying capacity of plated through holes? TIA Geoff Layhe www.lamar-uk.co.uk Private & Confidential: This e-mail message is confidential and is intended solely for the person or organisation to whom it is addressed. If the message is received by anyone other than the addressee please return the message to the sender by replying to it and then delete the message from your computer. ---------------------------------------------------------------------------- ----- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------- ----- ---------------------------------------------------------------------------- ----- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------- ----- --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d To unsubscribe, send a message to [log in to unmask] with following text in the BODY (NOT the subject field): SIGNOFF Technet To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ---------------------------------------------------------------------------------