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TPS6521835: Use TPS6521835 instead of TPS65218D0 ?

Part Number: TPS6521835
Other Parts Discussed in Thread: AM4377, TPS65218D0, , TPS6521815, BOOSTXL-TPS65218

Hello TI enthusiasts,

We have an existing product which uses an AM4377 CPU with TPS65218D0 power management IC. We are looking into possibility to use TPS6521835 instead, after first configuring each IC to the voltages that match the default config of TPS65218D0. Does this have a chance to work? After looking at the datasheets we concluded that the config memory is non-volatile, and the pin and register compatibility is there, so the only difference between the ICs (they are tailored for two different CPUs) is in the default voltages. Is there anything we are missing?

  • Hi Nurgak,

    You will need to put the TPS6521835 in the ACTIVE state to gain access to I2C communication and programming. As long as you can do that without damaging the surrounding components you can change the registers to match the TPS65218D0 where necessary.

    I would recommend you look through Section 8.5 of the TPS6521815 datasheet to see how the programming usually works for these devices (password protected registers). The instructions for the TPS6521815 should also work for the TPS6521835. However, as I mentioned above, the TPS6521835 power rails are already set with a certain VOUT and power-up sequence. You cannot change these power-up settings before turning on the device.

    The TPS6521815 is different because none of the power rails are set up by default and you can move to the ACTIVE state without risk of using the wrong voltage outputs or sequencing.

    Regards,

    James

  • Hi James,

    Thanks, the hints about TPS6521815 help a lot! The plan for TPS6521835 would be to pre-program each part externally before it even goes to the pick-and-place machine. Then once it is in circuit, it should start with the new voltage settings. The TPS6521815 looks nice but it is impossible to buy it so it doesn't help.

    I have another question regarding the default register values of TPS65218D0. In the datasheet the default voltages are listed, but I cannot find what are the default sequencer settings. Ideally I would like to have the defaults of the entire register memory so that I can copy the relevant settings to the config of TPS6521835. Do you know if there is a place where I can find such info about the TPS65218D0 default registers?

    Regards.

  • Hi Nurgak,

    The full register list starts at Section 5.6.4 in the TPS65218D0 datasheet and you can use Table 5.6 to jump to any register you want. Check the reset column in the bit description section to find the default bit values for each register.

    If you go to Section 5.6.4.21you will find the first sequence related register, SEQ1. The subsequent sections should cover registers SEQ2 through SEQ7. 

    Regards,

    James

  • Hi James,

    Thanks for your help! I am ordering the BOOSTXL-TPS65218 evaluation kit for programming the ICs and I will start playing with it.

    Regards.