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Altera_Forum's avatar
Altera_Forum
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15 years ago

Number of RUP, RDN pairs for SO-DIMM?

How many RUP,RDN resistor pairs would need to be connected when using termination calibration blocks for a 64-bit DDR SO-DIMM? I would like to add these resistors to my next board spin but I'm not qu...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

Thanks, then 1 RUP/RDN pair is sufficient for my design.

One more thing; what is the calibration block actually doing? Automatically tuning the termination resistor to get as close to 50 ohm termination as possible regardless of PVT?

I'm considering the option of using non-calibrated 50 ohm serial termination for my 200 MHz DDR interface. What are the practical implications of non-calibrated vs calibrated serial termination at these low speeds? I have a feeling non-calibrated would work just fine but would love to get some input on the matter.

Thanks.