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LMZ30604: Pull Up and Pull Down resistor value of INH pin

Shinichi Inoue
Guru 20916 points
Part Number: LMZ30604
Other Parts Discussed in Thread: TPSM82866A, TPSM82864A, SN74HCS05

Dear Specialists,

Our customer has a question.

---

INH pin of LMZ30604 has  Pull Up and Pull Down resistor in the device.

Could you please let us know the value of Pull Up and Pull Down resistor. 

---

I appreciate your great help in advance.

Best regards,

Shinichi

  • 0
    TI__Genius 14876 points

    Hello Shinichi,

    Have you had a look at the newer, smaller and more efficient TPSM82864A/TPSM82866A power modules ?

    The enable/inhibit scheme for this part is simpler and multiple in parallel can be controlled.

    Let me know if you have any questions.

    Thanks a lot!

    Regards,
    Dorian

  • 0 in reply to Dorian Brillet de Cande
    Guru 20916 points

    Hi Dorian,

    Thank you for your reply.

    I'll introduce TPSM82864A. 

    Could you please let us know the original question.

    Regarding LMZ30604, how are the value of pull up and pull down resister value. 

    I appreciate your great help and cooperation.

    Best regards,

    Shinichi

  • 0 in reply to Shinichi Inoue
    TI__Genius 14876 points

    Hello Shinichi,

    INH pin of LMZ30604 has only a pull-up current source, which allows customer to leave the INH pin floating for enabling the device.

    INH does not have a pull-up and pull-down resistor has suggested. You may want to double check the Output On/Off Inhibit (INH) (Topic 8.9), in case you missed any information.

    Let me know if you have any further questions.

    Thanks a lot!

    Regards,
    Dorian

  • 0 in reply to Dorian Brillet de Cande
    Guru 20916 points

    Hi Dorian,

    Thank you for your reply.

    I understand INH doesn't have a pull-up and pull-down resister and confirmed external pull-down resister in Figure 33.

    I'll share this information with the customer.

    When the customer has an additional question, I consult you again.

    I appreciate your great help and cooperation.

    Best regards,

    Shinichi

  • 0 in reply to Shinichi Inoue
    TI__Genius 14876 points

    Hello Shinichi,

    Thank you very much for letting me know.

    Regards,

    Dorian

  • 0 in reply to Dorian Brillet de Cande
    Guru 20916 points

    Hi Dorian,

    I have one additional question, could you please advise.

    You mentioned there are no pull-up and pull down resister at INH pin.

    On the other hand, the datasheet P.5  FUNCTUINAL BLOCK DIAGRAM describes Pull-up and Pull-down resister.

     Are there typo?

    I'm looking forward to waiting your comment.

    I appreciate your great help and cooperation.

    Best regards,

    Shinichi

  • +1 in reply to Shinichi Inoue
    TI__Genius 14876 points

    Hello Shinichi,

    You refer to the INH/UVLO. For the INH functionality a pull-up current source is implemented using an adapted Control Logic and pull-up resistor. A different logic is also implemented for the UVLO feature INH .

    What you see in the Functional Block Diagram is a Pull-up and Pull-down but are not only used for the INH. 

    The value of these resistors are not tested and validated. What is customer concern here ?
    Functionality and how to implement the different features, either INH or UVLO, are described in the datasheet.

    Let me know.

    Thanks,

    Dorian       

  • 0 in reply to Dorian Brillet de Cande
    Guru 20916 points

    Hi Dorian,

    Thank you for your reply.

    The customer is considering SN74HCS05 instead of  FET. They concerned about drive current.

    In this case, constant current is 100uAmax and 700uA in 7 INHs.  

    On the other hand, SN74HCS05 has +/-35mA that is enough to drive 7 INHs.

    The customer satisfied this comment.

    So let's close this thread.

    I appreciate your great help and cooperation.

    Best regards,

    Shinichi