This may or may not be an option for you considering you are running at= 100MHz, but... We had a similar problem on a large FPGA with wide buses. Since the SSO= noise seemed to be related to the package and not the board, the only= option we could see was to change the I/O drivers to slow down the edge= rates on the output drivers of those wide buses. It worked beautifully. David Kaiser 4 McDATA Pkwy. Broomfield, CO 80021 (720) 558-4431 david.kaiser@xxxxxxxxxx -----Original Message----- From: Fabrizio Zanella [mailto:fzanella@xxxxxxxxxxxx] Sent: Wednesday, June 25, 2003 10:02 AM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Reducing SSO noise in an FPGA I would like to hear about experiences regarding methods of reducing simultaneous switching noise in a large FPGA, BGA package. Let's assume a 128bit bus, with a signal frequency of 100MHz. How effective is adding ground planes 2 mils from the VCC planes in reducing SSN? If one uses BC, does every VCC pin in the FPGA require decoupling? And should the caps be tied to the BGA pins with blind vias so they can be placed directly under the BGA? What are the optimal values for the decoupling capacitors, 0.1uf, 0.22uF? Thanks very much and regards, Fabrizio Zanella Principal Hardware Design Engineer Broadbus Technologies fzanella@xxxxxxxxxxxx =3D20 -------------------------------------------------------- =3D20 This email message and any files transmitted with it contain =3D confidential information intended only for the person(s) to whom this =3D email message is addressed. If you have received this email message in =3D error, please notify the sender immediately by telephone or email and =3D destroy the original message without making a copy. Thank you.=3D20 =3D20 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: http://www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: =20 http://www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages=20 Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu =20 SPECIAL NOTICE=20 All information transmitted hereby is intended only for the use of the= addressee(s) named above and may contain confidential and privileged= information. Any unauthorized review, use, disclosure or distribution of= confidential and privileged information is prohibited. If the reader of= this message is not the intended recipient(s) or the employee or agent= responsible for delivering the message to the intended recipient(s). You may not distribute or copy the confidential and privileged portion of= this communication to another. Anyone who receives confidential and= privileged information in error should notify us immediately by telephone= and mail the original message to us at the above address and destroy all= copies. To the extent any portion of this communication contains public= information, no such restrictions apply to that information. (gate01) ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: http://www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: http://www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu