• State Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 1 answer
  • Subscribers 100 subscribers
  • Views 525 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DM3730: POP package , replacing 4Gb with 8Gb LPDDR & MUX16

Colombo Carlo
Mastermind 24120 points
Part Number: DM3730

Hi everybody , 

I would like to mount 8Gb instead of 4Gb  ( due to availability )   without any changes to my code and OS ( using only 4Gb out of newer memory ) .

in particular we do not want changes in muxing and as per TRM it looks like MUX16 can do this ,.

we did a  first test on a board and it worked  but we would like confirmation no issue  can happen 

is it correct what we are doing ?    memory organization is the same 

regards

Carlo

  • 0
    TI__Guru 65405 points
    Hi Carlo,

    If we assume that the new 8Gb LPDDR chip is pin to pin compatible with the 4Gb one you should no need to make any changes. Of course, as you note, the system will using only 4Gb of memory.

    Regards,
    Tsvetolin Shulev
  • 0 in reply to Cvetolin Shulev-XID
    TI__Mastermind 24120 points
    HI Tsvetolin Shulev
    yes I m moving from :
    - 4Gb: Micron MT46H128M32L2KK-48 WT:C
    - 8Gb: Micron MT46H256M32L4SA-48 WT:C

    so do you see any need for change to be made on the MUX16 ?
    thank you
    regards
    Carlo
  • 0 in reply to Colombo Carlo
    TI__Guru*** 125430 points

    Colombo Carlo said:
    so do you see any need for change to be made on the MUX16 ?

    How many column, row, and bank pins are in each LPDDR device?

    Colombo Carlo said:
    - 4Gb: Micron MT46H128M32L2KK-48 WT:C
    - 8Gb: Micron MT46H256M32L4SA-48 WT:C

    I couldn't find a data sheet for the 4Gb device.  Have they carefully compared all the timing parameters to see what has changed?  I would expect some of the timings will be different.  However, they can still come up with one set of timings that will work for both their old RAM and their new RAM.  They just need to choose the more conservative timing any place where they differ.

  • 0 in reply to Brad Griffis
    Intellectual 290 points

    Hi Brad,

    the two LPDDR devices have exactly the same pinout.

    Furthermore the 4Gb is a stack of two 2Gb 64Mx32 dies while the 8Gb is a stack of four 2Gb 128Mx16 dies; according to the datasheet the two 2Gb dies (x32 and x16) have exactly the same timing.

    Please let me know if you need further information.

    Many thanks in advance for your support.

    Marco

  • 0 in reply to Marco Caldari
    TI__Guru*** 125430 points
    As long as you're ok with only accessing half of the available memory (e.g. perhaps for easy backward compatibility), then I don't see any issue with MUX16.