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TPS65219: LDO Programmable Output

Shaofeng Luo
Intellectual 1650 points
Part Number: TPS65219

Hi team

Customer is designing power rail around AM62 and DP83867, they want to save an external LDO for PHY VDD1P0(1V), so they want to use TPS6521901 LDO2 as this supply. So they need to program the output from 0.85V default to 1.0V via I2C. Do you think it's OK for this application? Can this operation be saved in EEPROM and power up with 1.0V next time? Thanks!

By the way, they will change BUCK1 from 0.75V to 0.85V and power the VDD_CORE and VDD_DDR_CORE.

  • 0
    TI__Mastermind 22156 points

    Hello, 

    Thanks for reaching out!  Is this a non-automotive application? What memory is the customer planning to use? DDR4 or LPDDR4?

    For non-automotive AM62x applications using 3.3V input supply, DDR4 and VDD_CORE=0.85V we recommend using TPS6521904. The LDO2 (1.8V by default) from this orderable part number is a free power resource that can be used to supply any external peripherals. This PMIC comes with the FSD feature enabled; It means PMIC will go from NO Power to the Active state (executing the power-up sequence) as soon as the input supply is above the POR threshold. Once the PMIC is in Active state (all power rails enabled), the LDO2 output voltage can be changed through I2C. 

    Just want to highlight, the FSD feature (first supply detection) will prevent the customer from making changes to the LDO2 output voltage (or any other register setting) before the power-up sequence is executed. 

    Link to the AM62+TPS65219 Apps note: Powering the AM62x with the TPS65219 PMIC (Rev. A) 

    Thanks,

    Brenda

  • 0 in reply to Brenda Diaz
    TI__Intellectual 1650 points

    Hi Brenda

    Thanks for your quick reply! DDR4 is used in this non-automotive design. We know that 04 version is suitable for 0.85V design, but LDO2 is 1.8V default, it exceeds the 1.0V power supply of PHY, that's why we still want to use 01 version here. It seems that it would be more convenient to add a LDO for PHY 1.0V VDD. 

  • 0 in reply to Shaofeng Luo
    TI__Mastermind 22156 points

    Hi Shaofeng,

    Yes, I would recommend using the TPS6521904 (which has BUCK1=0.85V) with an external LDO to supply the 1.0V for the Ethernet PHY. The AM62-SK EVM (design files available at the link below) shows an example of how the rails of the Ethernet PHY were supplied by the PMIC and the external LDO. Please note, this EVM is using a different variant of the TPS65219 PMIC. 

    https://www.ti.com/lit/zip/sprr453

    Thanks,

    Brenda