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i.MX6DQ DDR tDS and tDH.

Question asked by Satoshi Shimoda on Aug 5, 2015
Latest reply on Jan 26, 2017 by Yuri Muhin

Hi community,


I have some questions about i.MX6Q DDR parameter.

Please see Table 43 in IMX6DQCEC Rev.4 and my questions below.



I understand tDS and tDH should be calculated as below.

tDS (total setup time) = tDS(base) + delta tDS

tDH (total hold time)  = tDH(base) + delta tDH

Actually, the values of tDS and tDH in Table 43 are larger than the following values in JEDEC standard (JESD79-3F).

tDS(base) AC175 = 25 ps

tDS(base) AC150 = 75 ps

tDS(base) AC135 = 115 ps

tDH(base) DC100 = 100ps

So I think the value in Table 43 should be used for calculation instead of JEDEC standard value.

Is this correct?



I could not find the condition of tDS and tDH in Table 43.

Which condition is used for Table 43? (AC175 or AC150 for tDS, DC100 for tDH?)



I think the tDS and tDH values are actual phase difference between DATA, DQM and DQS on i.MX6Q pad.

Is this correct?



Can I use the same delta tDS and delta tDH values as JEDEC standard (JESD79-3F) to calculate even though tDS(base) and tDH(base) in Table 43 is different from JEDEC standard?



This post was rejected.

Would you let me know why this post was rejected? What should I edit?


Best Regards,

Satoshi Shimoda