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AM335x / TPS65217 3V IO?

DavidVescovi
Genius 5470 points
Other Parts Discussed in Thread: TPS65217

For a battery powered system I know it would be ideal to use the1.8v IO configured supply for a total 1.8v system. All the examples I have seen and all the lit. seems to spec. ether 1.8v IO or 3.3V for processor IO supply.

In my case I have some 3.0 volt peripherals. I know the TPS65217 PMIC has the ability to program the IO LDO to 3v.

Is this a valid combination for powering the AM335x? Is there any programming needed on the AM335x side to spec what IO voltage you are using or is it just what ever is connected to the VDDSHVx pin of the processor?

  • 0
    TI__Guru**** 393215 points

    Hi David,

    The AM335X specification requires a 3.3V +/- 5% or 3.135V to 3.465V for VDDSHVx in 3.3V mode (AM335X Datasheet Rev. G section 5.5). Different signal pins' I/O cells are connected to one of the VDDSHVx rails, check Table 4-1 in the datasheet). Any VDDSHVx rail can be connected either to 1.8V or 3.3V and all the I/O cells that are powered from this rail will operate at the corresponding voltage. There is no AM335X programming involved.

    As for your use case, you can check if the external 3.0V peripherals are tolerant to 3.3V signals.

  • 0 in reply to Biser Gatchev-XID
    Genius 5470 points

    Thank you for the reply.

    My peripherals have to run at 3.0 volts nom. and that is why I was investigating if VDDSHVx can be run at 3.0v.

    I understand if you are running at 3.3v nominal you have +-5% tol. I can understand the spec. sheet being shown with 1.8v and 3.3v nom. as they are the most common configurations.

    I am wondering if VDDSHVx can be run at 3.0v nominal? If it can take 1.8v or 3.3v and there is no programming restriction I assume it can be set at any voltage in between????

  • 0 in reply to DavidVescovi
    TI__Guru**** 393215 points

    This is not correct. AM335X I/O cells must be supplied either from 1.8V+/-5% or 3.3V+/-5% No other voltages are allowed.