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TPS659037: Regarding 16MHz OSC

Daisuke Higa
Genius 3745 points
Part Number: TPS659037

Hi support team.

My customer has some questions that is below.

① Why is the external clock setting <Yes> for OTP?

(2) Is a 16.768MHz oscillator required externally?
Are there any settings or conditions that do not require the use of an external oscillator?

③ If an external clock is required, is it possible to replace it with an oscillator (1.8V) instead of an oscillator?

I appreciate if you give me an advice.

Best regards,

Higa

  • 0
    TI__Genius 12735 points

    Hi Higa-san,

    Please see my answers below:

    1. Can you be more specific about which TPS659037 variant you are looking at? I can also recommend reviewing the TPS659037 User's Guide to Power AM574x, AM572x, and AM571x which will detail how to connect each of the devices.

    2. Depending on which version of TPS659037 you are using the oscillator may or may not be required. This is detailed in the user's guide above.

    3. I am not sure what this question is referring to, can you please clarify?

    Best regards,

    Layne J

  • 0 in reply to Layne J
    Genius 3745 points

    Hello Layne-san

    I apologize for poor information.

    The device is TPS6590378.

    There was an error in the No. 3 question, so I corrected it. 

    --------------------------

    ① Why is the external clock setting <Yes> for OTP?

    (2) Is a 16.768MHz oscillator required externally?
    Are there any settings or conditions that do not require the use of an external oscillator?

    ③ If an external clock is required, is it possible to replace it with an oscillator (1.8V) instead of cristal resonant?

    --------------------------------

    Best regards,

    Higa

  • 0 in reply to Daisuke Higa
    TI__Genius 12735 points

    Hi Higa-san,

    Thank you for the clarifications. 

    1. TPS6590378 was designed for an application with AM574x/AM572x/AM571x processors and in those cases it was determined the 16 MHz oscillator was required to improve startup time. 

    2. If the external clock setting is enabled in the OTP settings then the oscillator circuit is required for proper operation.

    3. I would recommend using the 16.384 MHz crystal as recommended in the datasheet. Other options can be tested on an EVM but I have not tested this myself in the past.

    Best regards,

    Layne J

  • 0 in reply to Layne J
    Genius 3745 points

    Hi Layne-san

    Thank you for your prompt reply.

    I write my comment and additional questions in line.

    >1. TPS6590378 was designed for an application with AM574x/AM572x/AM571x processors and in those cases it was determined the 16 MHz oscillator was required to improve startup time. 

    [Higa] I understand that it is more better but not mandatory, is it correct? 

    >2. If the external clock setting is enabled in the OTP settings then the oscillator circuit is required for proper operation.

    [Higa]  I understand that external clock setting is disabled in the OTP settings then the oscillator circuit is not required, is it correct?

    >3. I would recommend using the 16.384 MHz crystal as recommended in the datasheet. Other options can be tested on an EVM but I have not tested this myself in the past.

    [Higa] I understand. Thank you.

    Thank you for your cooperation.

    Best regards,

    Higa

  • 0 in reply to Daisuke Higa
    TI__Genius 12735 points

    Hi Higa-san,

    1. It is not mandatory if the PMIC does not have the external clock enabled in the OTP. However, in this case both possible OTPs have the external clock enabled and will require the crystal to operate properly. To avoid this they can attempt to use the TPS659039x devices which are the automotive variant of this device designed to power the DRA7x processors (automotive processors). In the TPS659039-Q1 User’s Guide to Power DRA74x, DRA75x, TDA2x, and AM572x which details the different OTP versions for this device. There are 2 variants of TPS659039 not requiring the crystal but keep in mind the pricing may end up being higher when compared to TPS659037 with the external crystal due to the automotive rating on the TPS659039 device.

    2. If the external clock setting is disabled in the OTP then the crystal is not required, this is correct.

    Best regards,

    Layne J

  • 0 in reply to Layne J
    Genius 3745 points

    Hi Layne-san

    I have additional questions blow.

    Is the TPS6590378 OTP shipped with a 16MHz crystal written as a valid setting?

    If YES, is it possible to rewrite the 16MHz crystal to the OTP memory again to the invalid setting?
    (It is recognized that OTP memory is non-volatile and can be written only once.)

    If that is not possible, then the 16MHz crystal would have to be implemented from the beginning and the device would have to be changed.

    Is this idea correct?

    I appreciate if you provide some information regarding it.
    Let me know if you have any question.

    Best regards,
    Higa

  • 0 in reply to Daisuke Higa
    TI__Genius 12735 points

    Hi Higa-san,

    It is not possible to change the OTP settings on a device that has been already programmed. Both of the released TPS659037x devices intended for use with AM57x processors are configured to have the crystal enabled in the OTP. If the crystal is enable in the OTP then the device requires the crystal be used at all times when operating the board.

    Best regards,

    Layne J

  • 0 in reply to Layne J
    Genius 3745 points

    Hi Layne-san

    I apologize for my late response.

    Thank you for your reply.

    I understand.

    Best regards,

    Higa