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TPS53355: Compatible with TPS53319 Consult

Stanley Dai
Expert 5810 points
Part Number: TPS53355
Other Parts Discussed in Thread: TPS53319, , TPS53353

Hi Team,

Customer wants to use TPS53355 to replace TPS53319 in their board because of device shortage. I check both D/S, these footprints are same. Do you think are there peripheral circuits customer needs to adjust in this case? Pls help us here.

Best,

Stanley

  • 0
    TI__Mastermind 23695 points

    The TPS53319 and TPS53355 are based on the same controller. 

    Use the excel calc sheet https://www.ti.com/lit/zip/sluraz7 to compare any necessary changes.  I do think there will be any adjustments other than the ROVP on TPS53319 and NC on TPS53355  for pin 5. 

    The light load efficiency will be lower for the TPS53355 vs TPS53319. 

  • 0 in reply to David_Daniels
    TI__Expert 5810 points

    Hi Daniel,

    Many thanks for your helps. Yes, the pin5 of TPS53319 is connected with Vout through resistor for achieving OVP. The pin5 of TPS53355 is N/C. So is that okay to keep these connections of pin5 when doing replacement? Or customer must leave no connect for TPS53355's pin5?

    Looking for your confirmation.

    Best,

    Stanley 

  • +1 in reply to Stanley Dai
    TI__Mastermind 23695 points

    The PIN 5 on TPS53355 is NC and there is no internal connection from the pin to the die, I check the drawings. The preferred installation would be DNP the resistors on ROVP.    But it should be acceptable to leave resistors connected since the PIN5 has no connection to the die.

  • 0 in reply to David_Daniels
    TI__Expert 5810 points

    Hi David,

    Thanks for your above comments. Adding one abnormal phenomenon when customer is doing the replacement, which needs your further helps.

    The RRF in customer schematic is 866kohm connected with VREG.  For TPS53319, the tested frequency is around 540kHz, which is in our D/S range. But for TPS53353, the tested frequency is around 550kHz, which is beyond our D/S note range.

    And RRF frequency setup table for TPS53319 and TPS53355 is almost same except for 866kohm. I wonder there is possibility that TPS53353's D/S may have a mistake in 866kohm frequency setting. You may look at below two D/S screenshots for details.

    • TPS53355:

    • TPS53319

    Waiting for your confirmation.

    Best,

    Stanley

  • 0 in reply to Stanley Dai
    TI__Mastermind 23695 points

    To be honest, I think both datasheets have mistakes.   

    When I test the TPS53319 and TPS53353 evm  with 600/650 setting at a vout of 1.5V (VIN=12V) I get 626kHz and 634kHz respectively.   

    So 600 kHz and 650 kHz may not be the ideal numbers to represent the settings. 

    There is also a dependency with vout. At vout of 0.6V, with a 600kHz setting, i get 464kHz for the TPS53319.

  • 0 in reply to David_Daniels
    TI__Expert 5810 points

    Hi David,

    Is that possible for u to provide a latest frequency table guide to customer, since D/S data is not valid? You know there is test standard regarding to frequency setting accuracy which should be within ±10% in customer side. 

    Pls feel free to contact me through e-mail if needed. We do need your helps in this frequency setting issue.

    Best,.

    Stanley

  • 0 in reply to Stanley Dai
    TI__Expert 7500 points

    Hi Stanley,

    Please wait. David will feedback to you on Monday US time or you can contact through email.

    Thanks,

    Lishuang

  • 0 in reply to Stanley Dai
    TI__Mastermind 23695 points

    I will close here and email direct