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TMS320C6748: Could the power supply ref design using TPS650061 be changed?

user1854915
Prodigy 180 points
Part Number: TMS320C6748
Other Parts Discussed in Thread: TPS650061, OMAP-L138

Hi,

The power supply ref design using TPS650061 ( from the Application Note SLVA490 ) is as below. Could i change the 1.2v to 1.3v to make  the DSP operate at 456MHz?

Best Regards,

Kevin Clooney

  • 0
    TI__Guru**** 161600 points
    Hi,

    If you mean that you want to change the voltage provided by DCDC VOUT of TPS650061, then yes (this is stated in TPS650061 datasheet). This is externally adjustable.

    Have a look at the PMIC datasheet. Equation 1 in section Feature Description (continued) describes how you can achieve this. For the purpose you need to adjust the external to the PMIC resistor network on the output.

    Best Regards,
    Yordan
  • 0 in reply to Yordan Kovachev
    Prodigy 180 points

    Hi Yordan,

    Thanks for your reply. Maybe my quesiton is not clear enough, and i am sorry for that. I will explain that more clearly.

    The datasheet shows that the CVDD and RVDD should be 1.3V to make the C6748 operate at 456MHz. If i promote the VODC of the ref design using TPS650061 from 1.2V to 1.3V only and the rest of ref design using TPS650061 remain, the voltage would not exceed the maximum value as below. But will this change still follow the power-on sequence, could i use the ref design ( 1.3v TPS650061 VODC ) to power  on C6748 successfully?

    Best Regards,

    Kevin Clooney

  • 0 in reply to user1854915
    TI__Guru**** 161600 points
    Hi Kevin,

    Yes, this should be possible. The app note (SLVA490) recommends TPS650061 for powering up the OMAP-L138 SoC, so the PMIC OTP should be programmed to comply with OMAP-L138 power-up sequence. Changing the VODC voltage through external resistor network should not change the sequence in which the PMIC will turn on the voltages.

    Let me confirm this with the design team, but in my opinion this should be possible.

    Best Regards,
    Yordan