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DDR2 Signal Integrity

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chamarnadh

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HI,
Can you explain how we eliminate the ringing, overshoot and under shoot in the following DDR2 device.I am interfacing with MPC8378controller and DDR2 is MT47H128M16.
I am unable to eliminate the ringing.
Iam simulating through Hyperlynx and i am using controlled impedance stackup. please observe the attachment and comment.


Can any body help me .

Thanks in advance
Amarnadh
 

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marce

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Do your Hyperlinx waveforms match the scope waveforms?
Have you modeled the scope probe?
The non-monotonic rising and falling edges are of concern.
 

marce

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Have a look at AN246 from this page, it explains in relatively simple terms how reflections cause what you see on your waveforms. Finding the culprit impedance mismatch point can be fun.
 

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