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View Full Version : Pull-up resistors w/ tracks for DDR2 SDRAM.


fiedel
Dec3-10, 05:32 PM
When pulling up DDR2 signals with resistors, how to decide the power consumption of them, or I can just use 0402 resistors? And for the tracks connecting the resistors to the VTT (or the resistors to the signals), is there a impedance matching problem? Should them be of the same length?

JimmyAlz
Dec4-10, 05:34 AM
Take a look at a PC mainboard that uses DDR2. The pull-ups are easy to find. Just use the same size as that manufacturer uses. Yes from what I understand length is critical. Again take a look at a PC mainboard, you will see many "wiggly" lines that adjust the lengths. I don't know about impedances though.

fiedel
Dec6-10, 02:42 PM
I thought the wiggly lines are such signals like data and address, but not pull-ups...