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DM3730: Redesigning the board to avoid POP memories

Part Number: DM3730

From field:

In the past customer selected POP package (8Gbit, 4 dies validated by TI in pop )   due to our note on wiki :

AM37x Hardware connections to SDRAM

This section will discuss the connections and recomendations for connecting to LPDDR1 memories.  The AM37x SDRAM interface opperates at a maximum of 200MHz allowing connection to 400LPDDR1 devices.  The interface supports 1GByte over 2 Chip Selects.  The SDRC signals should never exceed 2 loads.  Some memories increase capacity by stacking dies in their packages.  Each die in the memory device adds a load to the SDRC signals, so if a memory has 2 dies in the device then the AM37x SDRC signals will have 2 loads present.

The SDRC signals should never exceed 2 loads

 

Now  customer could  have these different choices    in  CUS  package  :

 

1)      4x2Gbit LPDDR (1Die each)

2)      2x4Gbit LPDDR (2 Dies each)

3)      1x8Gbit LPDDR (4 Dies)

 

Is  any of this  choice  acceptable  on CUS ?    are  they are hitting  the 2dies issue …?

  • Moving this to Sitara forum as the text says AM37x.
  • Basically, if they need 8Gb (1GB) here are some options (also listed in Table 6-13 of the Data sheet). You can pick and chose based on the availability.

    - 2 instances of x16 4Gb memory

    - 1 instance of x32 8Gb memory

    Let us know if you have any further follow up questions

    Regards, Siva

  • Dear Siva, thanks for the answer. In the Table it is listed to be used MAX 2xJEDEC LPDDR device.

    A Jedec LPDDR device is a 2Gbit Device (Single Die). Please see attached datasheet at pag 2 for Part Number selection.

    The 8Gbit LPDDR is made by four dies of the Jedec standard 2Gbit LPDDR. At least this is what I can understand.

    My question is: Can I use the L4 = 4-die stack standard addressing with BGA package? 

    We are currently using the PoP device that was certified and tested by TI, but since this type of device are in EOL we would like to know if it is possible to use the BGA type. Please mind the WIKI notes shown by Carlo Colombo on him previous mail. This is a very important and urgent issu we have to fix very soon.

    Best regards2-8Gbit.pdf

    Mauro

  • Mauro Palombini said:

    A Jedec LPDDR device is a 2Gbit Device (Single Die). Please see attached datasheet at pag 2 for Part Number selection.

    The 8Gbit LPDDR is made by four dies of the Jedec standard 2Gbit LPDDR. At least this is what I can understand.

    My question is: Can I use the L4 = 4-die stack standard addressing with BGA package? 

    As I stated earlier, L4 is not an option with CUS package. L2 is an option if it is a dual channel, single rank device using a single chip select. Basically, we cannot support dual rank system

    Mauro Palombini said:

    We are currently using the PoP device that was certified and tested by TI, but since this type of device are in EOL we would like to know if it is possible to use the BGA type. Please mind the WIKI notes shown by Carlo Colombo on him previous mail. This is a very important and urgent issu we have to fix very soon.

    The wiki link reflects the controller capabilities, but does not cover the CUS specific capabilities. Datasheet lists clearly the device capabilities and supported configurations. Let me know if you have any more questions

  • Dear Sivak, Thanks a lot for your help. We knew what stated on the datasheet and understand the meaning but, since this is an important issue, we wanted to ask confirmation from TI. Now we got it and we know how to proceed in order to fix the problem of the lack of the PoP memories. This is a common problem to all TI DM3730CBP users.

    Thanks a lot again and best regards

    Mauro