This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS65219: VSYS voltage of TPS6521907

Part Number: TPS65219

I am considering using the TPS6521907 as a power supply for the AM62x.

[Question.]
I think 5V is the recommended condition for VSYS, but is there any problem in operation if I input 3.3V?

[Condition]
The 3.3V output of Buck2 is not used.
I think that Buck Converter requires 0.7V potential difference between input and output voltage, but 3.3V output of Buck2 is not used.(I am attaching part of the data sheet.)

[Appendix]
The core voltage of AM62x is 0.85V and memory is DDR4,
The factory-programmed model of TPS65219 must be TPS6521904 or TPS6521907.
The TPS6521904 cannot be used because PB is assigned to the EN/PB/VSENSE pin.


  • Hi,

    TPS6521907 must be supplied with a minimum of 4V on VSYS. The reason, as you highlighted, is because the BUCKs require 0.7V headroom and Buck2 is configured to output 3.3V (3.3+0.7=4V). The headroom requirements must be followed for all the rails that are enabled by default (i.e Buck2) even if they are not used in the application. The PMIC uses the internal power good signal from each rail as a reference to successfully execute the power-up sequence. 

    If the application uses 3.3V input supply, DDR4 and VDD_CORE=0.85V, then I would recommend using TPS6521904. Customer's also have the option to create a custom NVM using the user-programmable version (TPS6521905).

    Please note that both, TPS6521907 and TPS6521904, have the first supply detection (FSD) enabled by default. This means the PMIC ignores the state of the EN/PB/VSENSE pin during the first power-up (until nRSTOU is released). How is the customer planning to drive the enable pin of the PMIC?

    Thanks,

    Brenda