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Original question:

TPS53915: Could TPS53915 be TPS53513 alternate source?

TPS53513: Pins 27 & 28 configuration

Mega Drive
Prodigy 20 points
Part Number: TPS53513
Other Parts Discussed in Thread: TPS53915,

I would like to make a design to place either the TPS53915 or the TPS53513.

Question abotu pins 27 & 28 when using the TPS53513 - if these are connected to I2C pins of a micro or FPGA and held low with a low output impedance, would this be okay or do they HAVE to be connect to local gnd?

Thanks 

  • 0
    TI__Expert 7376 points

    The TPS53915 and TPS53513 are the same material up until the device is trimmed.

    Pin 27 and pin 28 are the test and trim interfaces for the devices.
    You can treat pin 27 and pin 28 on the TPS53513 the same as the TPS53915.

    If the pins on TPS53513 can not be grounded, tying the pin high and disconnected from the bus is next best. The 27,28 pins could be connected to the I2C bus, but the device would ACK commands if you wrote an address associated with the Pin 1 RF.

    If pins 27 and 28 can not be grounded or tied high, floating pins 27 and 28 is an acceptable option. Pins 28 and 27 are open-drain based and require an external pull-up to raise the voltage on the lines to communication. When floating the pins, the ability to drive the pins 27 and 28 with the proper voltage levels, timing, and PMBus command format is minimal.

  • 0 in reply to Tomoya Ide
    Prodigy 20 points

    Hi,

    Thanks for the quick reply.

    Can you confirm if we had a command to write to the device to make it run at 1MHz that if the TPS53513 was fitted instead of the TPS53915, the device would accept that command and not cause us any problems? 

    Thanks 

  • 0 in reply to Mega Drive
    TI__Expert 7376 points

    Hi Adrian,

    TPS53513 would not accept the FREQUENCY_CONFIG command because the switching frequency is programmed through the pin 1 RF resistor divider. 

  • 0 in reply to Tomoya Ide
    Prodigy 20 points

    Hi,

    Yes I understand with the TPS53513 the RF pin sets the frequency, and we have it as such.

    What I would like to know is if we have a PCB and firmware that sets the frequency of the TPS53915 to 1MHz, what if then to the exactly same baord we fit a TPS53513 in place of the TPS53915? THe RF pin divider will be set to make it run at 1MHz, but what about the I2C commands? 

    Our original plan was to check the I2C bus for the TPS53915 but in understand now that the TPS53513 will also ACK if you try communication with it. 

    So now I am asking if on the TPS53513 we write a 1MHz clk will it just accept that command but ignore it or will there be some kind of I2C bus error? 

    Thanks 

  • 0 in reply to Mega Drive
    TI__Mastermind 30530 points

    Hello Adroan,

    We are looking into this. Tomoya will respond next week 

    Thanks

    Tahar

  • +1 in reply to Mega Drive
    TI__Expert 7376 points

    Hi Adrian,

    Mega Drive said:
    So now I am asking if on the TPS53513 we write a 1MHz clk will it just accept that command but ignore it or will there be some kind of I2C bus error? 

    TPS53513 will accept the command but will not update the switching frequency. 

  • 0 in reply to Tomoya Ide
    Prodigy 20 points

    Thanks for the quick reply