Honored ContributorCould you help me with a question about termination resistors.
I am designing a stratix III pcb with one DDR2 chip(micron). I think I should place external parallel termination resistors on stratix III side. However, the space of the pcb is limited. Is it necessary to place external parallel termination resistors on DQ and DQS pins.
Honored ContributorFor DDR ,it is not necessary. For DDR2 it is.
Honored ContributorFor Stratix III, is there not some form of active termination internal to the IO that makes them very effective with DDR2? (to allow termination in one direction and not the other?)
Honored ContributorYou do not need to place termination resistors for DQ/DQS lines when using DDR2, just use ODT.
I would suggest to do a simulation of your PCB layout if you have access to such a tool, it is very useful.
