TMS320C6747: 456Mhz version of device with 400Mhz CPU Freq

Part Number: TMS320C6747

Hi,

The title shows that the part number is C6747, but in fact, DA810. 

456Mhz part of DA810, running at 456Mhz, requires 1.3V (nominal) for CVDD, but does 456Mhz part, running at 400Mhz, require the same voltage ? I`m wondering if 1.2V might be enough to meet its operation condition. My customer is using 400Mhz part in their product, but because of its supply shortage, they are considering replacing 400Mhz part with 456Mhz one *without* HW/SW changes. I saw some specific AC timing parameters only for 456Mhz part in the datasheet. For example, EMIFB timing is different from 400Mhz part and 456Mhz one. Is AC timing of 400Mhz part applicable for 456Mhz part running 400Mhz ?

Best Regards,
Naoki

  • Hi Naoki,

    The title shows that the part number is C6747, but in fact, DA810.

    456Mhz part of DA810, running at 456Mhz, requires 1.3V (nominal) for CVDD, but does 456Mhz part, running at 400Mhz, require the same voltage ?


    Could you specify which device is this exactly? You can refer to device nomenclature Figure 7-1. Device Nomenclature, you can have 300 MHz (for Revision A), 375 MHz (for Revision B) and 456 MHz (for Revision B) devices.

    For the TMS320C6747 see Table 3-1. Characteristics of the C6745/C6747 Processor. The processor works at 456MHz (1.3V CVDD).

    Best Regards,
    Yordan

     


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  • In reply to Yordan Kovachev:

    As I mentioned, I`m actually asking about DA810 part. Because I couldn`t specify the part number on this e2e title (DA810 is not catalog part, so it may not be listed in part number candidates), I just temporally used C6747.

    So the  exact part numbers :

    - Current device : D810K013DZKB400
    - Replacement device : D810K013DZKB456

    Please note D810K013DZKB400 is running with allowed frequency, say 400Mhz, by configuring internal PLL registers controlled by their software appropriately. They suppose to keep the PLL configurations on D810K013DZKB456, so D810K013DZKB456 is expected to run at 400Mhz, rather than its max speed :456Mhz. Also, SDRAM clock speed won`t be changed. In this case, is it okay to use 1.2V (not 1.3V) for CVDD with D810K013DZKB456  ? If yes, can we refer 1.2V specific AC Timings with D810K013DZKB456 ? For example, the following red square in datasheet:

    Best Regards,
    Naoki

  • In reply to Naoki Kawada:

    Any update on this ? I`m waiting for your reply.

    Best Regards,
    Naoki
  • In reply to Naoki Kawada:

    Naoki-san,

    Thanks for bringing this to our attention. The official datasheet recommendation for 400 MHz seems to be fuzzy. In most places it indicates that 375 MHz is the max for 1.2V setting and 456MHz would require to use CVDD (1.3) except for the foot note provided under EMIFB Electrical and timing table.

    I will check on this with the design and systems team and get back to you ASAP . Appreciate your patience on this issue.

    Regards,
    Rahul

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  • In reply to Rahul Prabhu:

    The lead engineer who owns this datasheet is out of office this week. We will try to provide some guidance on this early next week. The responses will be specifically for D810x family and will not be applicable to c6747

     

     

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