Brian, If the length of these two tracks is 1 or 2 inches at 20mils distance, usually it should not be a problem, because SDA is around 1 Mbps and orders of magnitude less than SERDES. But there are some issues that you need to consider: - Say you have 300 mV budget for crosstalk on SERDES, and crosstalks from other lines are already close to the budget, so passing SDA line close to SERDES may cause crosstalk to surpass the budget, and you need to change something to bring it lower. - Crosstalk from SERDES on SDA usually cannot make SDA to malfunction. But more important issue is SDA line can be a good antenna for 10GB/s signal if it's on top or bottom layer, and you may have more trouble with EMI/EMC. - For an exact answer you need to do a post-routing simulation, for example with Hyperlynx. It does not take much time to do that. You can perform simulation on a few nets including SERDES and status lines close to them. Massoud Shakeri -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of tianluchuan2005 Sent: Monday, August 08, 2011 6:12 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] crosstalk I have a question need your help. There is a via, the net is SDA of I2C, is close to 10Gb/s SERDES, the distance is about only 20mils. And I am afraid if there is the crosstalk between the SDA and SERDES. I don't know if the distance is safe, or the SDA have no influence to SERDES ? Thanks ! -Brian Tian ------------------------------------------------------------------ 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: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List technical documents are available at: http://www.si-list.net List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu