Cortland, The holes or slots may also be required to meet the "Maximum unpierced conductor area" requirement of UL796 Standard for Printed-Wiring Boards for your particular PWB supplier. In the UL Recognized Component Directory (vol. 3, ZPMV2) it is listed as Maximum, Area, Diameter, Inches.
Regards, Larry Merchell Taiyo Yuden (USA), Inc. San Marcos, CA -----Original Message----- From: Cortland Richmond [mailto:[email protected]] Sent: Wednesday, January 24, 2001 8:38 AM To: Debbie Mallory; ieee pstc list Subject: Re: FW: [Fwd: [SI-LIST] : Copper balance] Debbie, Doug Powell explained it as "venting," where slots or holes are added to a plane in order to let vapor out. However, it is my belief that this is also done to keep copper balanced during the etching process. I may well be mistaken, but the EMI and signal integrity concerns we have with the practice are all valid. Cheers, Cortland ====================== Original Message Follows ==================== >> Date: 23-Jan-01 07:25:06 MsgID: 1077-23952 ToID: 72146,373 From: Debbie Mallory >INTERNET:[email protected] Subj: FW: [Fwd: [SI-LIST] : Copper balance] Chrg: $0.00 Imp: Norm Sens: Std Receipt: No Parts: 1 From: Debbie Mallory <[email protected]> Subject: FW: [Fwd: [SI-LIST] : Copper balance] List-Post: [email protected] Date: Tue, 23 Jan 2001 07:21:35 -0800 Cortland, I, too, am having problems passing radiated emissions because of 350Mz originating from a 50MHz processor that uses a 50MHz oscillator. I thought I understood thieving until you said you have to put it on the ground plane also. Can you explain further why and how thieving is applied to the ground plane? Thanks. Regards, Debbie Mallory Advanced Fibre Communications Largo, FL ====================== End of Original Message ===================== ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected] ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Jim Bacher: [email protected] Michael Garretson: [email protected] For policy questions, send mail to: Richard Nute: [email protected]
