Vias equivalent length problem about DDR3 on AM335x platform

Liu Xiansheng

I'm routing DDR3 on AM335x platform referring to BeagleBONE Black.(BBB) I found the constrains of BBB didn't consider the vias's compact on maching length,and the datasheet of am335x didn't mention that too.So i want to know if the vias equivalent length can be ignored when routing the DDR3 on AM335x board. Thanks!

over 9 years ago

0 Miroslav Kiradzhiyski XID over 9 years ago

TI__Mastermind 25235 points

Hi,

Our hardware engineer is currently on vacation, so I'll forward this to the factory team.

Best regards,
Miroslav

0 sivak over 9 years ago in reply to Miroslav Kiradzhiyski XID

TI__Genius 9575 points

For good delay matching, it is recommended that data lines within a given byte have the same # of VIA's and also routed on the same layer. We suggest that you follow all the DDR routing requirements for a robust DDR interface. If your question on the VIA length is for max. length calculations, please do use the VIA length also for the calculations. We will review the data sheet and make it more clearer in a future revision regarding the VIA length.

Regards, Siva

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Vias equivalent length problem about DDR3 on AM335x platform