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TPS53915: Could TPS53915 be TPS53513 alternate source?

Jim Tsai
Expert 4470 points
Part Number: TPS53915
Other Parts Discussed in Thread: TPS53513, TPS53515, TPS549A20, TPS548A20

Hi,

Could TPS53915 as TPS53513 alternate source?

What's the circuit design different?

  • 0
    TI__Expert 5261 points

    The difference between TPS53915 & TPS53513 are:

      • Pin 1: PMB Addr vs. Rf
      • Pin 26: Alert vs. DNC
      • Pin27: SDA vs. Gnd
      • Pin 28: SCL vs. Gnd

    The output current recommendation on the datasheet is 12A for TPS53915 vs. 8A for TPS53513.

    The controller and power stage are the same for TPS53915 and TPS53513.  Production test/trim are different.  The TPS53915 is trimmed to enable PMbus commands, making default fsw=400kHz. 

    Pin 27 and Pin 28 are the test and trim interface for the devices.

    If a TPS53915 is in a TPS53513 socket, the fsw would be 400kHz, and mode pin settings are the same for TPS53513 and TPS53915.  No issue with TPS53915 having Pin 27 and 28 grounded.

  • 0 in reply to Tomoya Ide
    TI__Expert 4470 points

    HI Ide,

    Thanks for the reply.

    When I use TPS53915, could you please double check below:

    • Pin 1: PMB Addr vs. Rf => Could I keep the divider resister on RF pin? Or non install the divider resister?
    • Pin 26: Alert vs. DNC => I think NC is OK.
    • Pin27: SDA vs. Gnd => Tie to GND is OK, right?
    • Pin 28: SCL vs. Gnd=> Tie to GND is OK, right?
  • +1 in reply to Jim Tsai
    TI__Expert 5261 points

    Hi Jim,

    You can keep the resistor divider on the RF pin populated or unpopulated, whichever is fine since PMBus isn't used.

    Yes, please tie pins 27 and 28 to GND.

  • 0 in reply to Tomoya Ide
    TI__Expert 4470 points

    Hi Ide,

    I would like to confirm with you, if  use TPS549A20 & TPS53915 as the 2nd source of TPS53513&TPS53515, whether FSW can only be fixed at 400KHZ?

    If use TPS548A20, can BOM to BOM to TPS53513&TPS53515 ?

  • 0 in reply to Jim Tsai
    TI__Expert 5261 points

    Hi Jim,

    The FSW of TPS549A20 and TPS53915 can only be changed via the PMBus function. Therefore, if PMBus is not used, there is no way to change it from the 400kHz pre-set value. 

    TPS548A20 can mostly be BOM to BOM with TPS53513&TPS53515 except the ILIM resistor (RTRIP) should be recalculated with the TPS548A20's low-side RDS(on) value.

  • 0 in reply to Tomoya Ide
    TI__Expert 4470 points

    Hi Ide,

    One more question.

    I use design tool which is downloaded form ti.com and the calculate result suggest to place feedforward Cap Cff.

    My question is the Cff is just suggestion to improve transient response, what if customer don't want to install the Cap?

    If the stability test (phase-gain) and transient test performance are pass, can we non-install the Cff?

  • 0 in reply to Jim Tsai
    TI__Genius 14797 points

    Hi Jim,

    Due to the Christmas and New Year's Holidays, Ide will reply you after the holiday.

  • 0 in reply to Jim Tsai
    TI__Expert 5261 points

    Hi Jim,

    Yes, you are right. If it satisfies the customer's stability and transient requirement without the Cff, installing it is unnecessary.