Part Number: AM5728
Hi Experts,
Our customer is developing MPU system board with AM5728 and is verifying signal qualities. Recently, customer had done DDR3 Compliance Test, however, their system fails to VIX test for Clock. Customer is using DDR3-SDRAM(DDR3L-1066) which is Micron DDR3 (MT41K256M16TW-107:P).
According to DDR3 specification, customer believe, it would be passed when VIX indicates from 525mv(=675-150) to 825mv(=675+150).
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VIX fo Clock
Pass Limits:-150.000000000 mV to 150.000000000 mV
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Customer tried to look into the reason for this failure and summarized their report. Attached it (DDR3_VIX_FOR_CLOCK_eng.xlsx)
As far as customer investigate, Clock signal was disturbed momentarily and rarely. As the result, customer found out that this signal was caught by tester and it failed.
Customer checked DDR3 power supply/DDR3's signals. Power supply and Data line are stable, however, ADD line and CMD line were disturbed. Customer suppose this behavior causes Clock distortion. Therefore, Customer means, there is possibility that either AM5728 or DDR3 memory is disturbing those lines.
Have you ever hear similar issue so far?
It will be appreciated if you will be able to share your advice/comments on this.
I suppose Experts may need the layout data around DDR3, however, customer would like to know there is possibility that either AM5728 is disturbing ADD line and CMD line.
Best regards,
Miyazaki
