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DAC38RF83: configure device to work without external SYSREF signal

Andrei Autushenka
Prodigy 20 points
Part Number: DAC38RF83

Hello, In my design I don't want to use external SYSREF since I use only a single IC. In the datasheet, I found few registers that were possible designed for (Internal SYSREF Register (LCMGEN), Counter for Internal SYSREF Generator Register (LCMGEN_DIV), SPI SYSREF for Internal SYSREF Generator Register (LCMGEN_SPISYSREF))
However; there's no information on how to configure this LCM generator.
Can you describe what I need to set in order to configure the device to work without an external SYSREF signal? How to calculate LCMGEN_DIV?

  • 0
    TI__Guru 65894 points

    Hi,

    With the DAC38RF83 designed for JESD204 subclass 1, the external SYSREF is expected to ensure alignment of the LMFC and also proper RBD release of the DAC38RF83 JESD204 core. We do not recommend using the LCM generator as it is a test mode only and we have not done exhaustive testing with the operation. I can have someone on our team to answer this question for your reference only.

    -Kang

  • 0 in reply to Kang Hsia
    Prodigy 20 points

    Hello Kang

    Thanks for the quick response, got it! I'd love to know how to enable it for testing purposes.

  • 0 in reply to Andrei Autushenka
    TI__Guru 65894 points

    Hi, Andrei,

    I have checked with the engineers. This feature was not functioning as expected and therefore we cannot recommend using this circuit. Please continue to use external SYSREF to start the JESD204 state machine. Sorry for the inconvenience.

    Thank you.