I'm using a DSP processor with one chip Micron DDR3 MT41J128M16JT in a project.

I read a lot about the termination resistors, but I'm still confused about if I really need those, I didn't start the layout yet, but I can try to match the traces lengths, so the skew will within the accepted range, and also in this chip there is ODT which is implemented in the Data lines, so termination resistors are not needed there.

So, the question is: Do I really need termination resistors when using single chip? or there are some tips I can use so I will be in no need for them?


As already noted, you should definitely have terminations to Vtt (0.75V for standard DDR3). This source must be able to both sink and source current. There are regulators available for this specific task.

The address and control group should be DC terminated (I used 40.2 ohm parts) and the clock pair should be ac terminated (clock and complement each with 40 ohm resistors, both tied to a 100nF cap which then goes to Vtt).

Note that there are many register settings that control DDR3 memory interfaces, and you have to be careful to get them all correct.

Micron remains a wonderful source of information on using DDR3 as well as anything else they make.


Well you can't easily add then back in if you do... I would say that since you are asking this question and it is likely your first design then yes you need them. Further regardless of who's parts you are using go read the micron app note about your topology (probably single part point to point).

If you said that you had careful simulated your design, perhaps planned to run it slowly and for some reason needed to save the very low cost of these parts perhaps I would say do it without but not likely :)

Keep in mind ddr3 has odt (on die termination) for the data lines. You should check out this micron appnote


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