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Original question:

TPS53319: Regarding Recommended operating condition for EN voltage

TPS53319: Regarding behavior when VDD is 4.5V

Daisuke Higa
Genius 4000 points
Part Number: TPS53319
Other Parts Discussed in Thread: TPS548A28, , TPS548A29, TPS548B28, TPS53318

Hi support team.

My customer asked me regarding behavior when VDD is 4.5V.

Recommended operating condition of VDD is 4.5V to 25V

In addition, Minimum VREG Spec in datasheet is 4.77V at VDD = 12V.

I think that minimum VREG output voltage will be 4.25V when VDD is 4.5V.

In this case, my customer is concerned about the behavior of internal circuit.

 (Especially, there is no abnormality in the protection circuit)

Does it work fine even if VDD is 4.5V?

Best regards,

Higa

  • 0
    TI__Mastermind 22100 points

    Give the customer an EVM and let them test at 4.5V.      

    At lower input voltage the VREG voltage is lower and the on resistance will increase.  I do not know of any abnormality at lower input voltage. 

    When the on resistance increases the efficiency will be lower.   The current limit is sensed on the low side fet.      

    The device works at 4.5V.

    Or you can use the TPS548A28 and work down to 3V with a smaller package. 

  • 0 in reply to David_Daniels
    Genius 4000 points

    Hi Daniels-san

    Thank you for answering.

    I understand that the accuracy of current limiting decreases as the VDD voltage decreases.

    Is this understanding correct?

    If yes, what is the VDD voltage that does not reduce the accuracy of the current limit?

    Best regards,

    Higa

  • 0 in reply to Daisuke Higa
    TI__Mastermind 22100 points

    Let us solve the customer issue with a different approach to the problem.     

    What does the customer need or what are they looking for?

    Promoting a 10 year old device  is not in our interest when we have a device release 2 years ago that works to down 3V and has an adjustable current limit  (TPS548A28).

  • 0 in reply to David_Daniels
    Genius 4000 points

    Hi Daniels-san

    Thank you for your reply.

    Can you answer my question?

    My customer is using TPS548A28, but the supply is poor and it is not available.

    Therefore, we are considering using TPS53319 instead.

    Unfortunately there are no other products available.

    Do you have any other advice?

    Best regards,

    Higa

  • 0 in reply to Daisuke Higa
    TI__Mastermind 22100 points

    The TPS548A28 is p2p to TPS548A29, TPS548B28 and numerous competitors devices. 

    The TPS53319 is pin compatible with TPS53318. 

    The TPS53319 on resistance will increase when the voltage on VDD transitions from 5V to 4.5V. 

    The PDK data on fet shows the LS on resistance will increase 10%.    Eq 3 in datasheet shows the impact rdson changes to IOCP

  • 0 in reply to David_Daniels
    Genius 4000 points

    Hi Daniels-san

    Thank you for your support.

    I have already introduced the product you proposed, but it is difficult to obtain anything other than TPS53319.

    We would like to remind our customers to pay attention to the conditions of use.

    Thanks,

    Regards,

    Higa