Because of the Thanksgiving holiday in the U.S., TI E2E™ design support forum responses may be delayed from November 25 through December 2. Thank you for your patience.

  • State Resolved
  • Locked Locked
  • Replies 8 replies
  • Subscribers 23 subscribers
  • Views 1513 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS7A6350-Q1 Bode plot

Atsushi Yamauchi
Genius 4810 points

I would like to confirm the stability for gain-phase characteristics.

We got the bode plot for LP2951-50-Q1 to you.

I attached the picure.

Do you have the data for TPS7A6333-Q1 (or TPS7A6533-Q1)?

If you don't have, could you please get and provide the data?

Best regards,

Atsushi Yamauchi

  • 0
    TI__Expert 5675 points
    Hi Yamauchi san,

    Yes, we could test the bode plot in our lab and provide the results in this week. However, as you know, frequency response is highly depended on the components connected, so the results could only for reference only.

    BTW, of which device customer would like to have? TPS7A6333-Q1, TPS7A6350-Q1 or TPS7A6533-Q1? If not specified, I would take the TPS7A6350-Q1 as example.

    Best regards,
    Jason Liu
  • 0 in reply to Jason. Liu
    Genius 4810 points
    Dear Jason-san,

    Thank you for your reply.

    The customer will use TPS7A6333-Q1, so could you please get the data of TPS7A6333-Q1?

    Best regards,
    Atsushi Yamauchi
  • 0 in reply to Atsushi Yamauchi
    Genius 4810 points

    Dear Jason-san,

    I'm sorry I mistook the name of IC. They need it  of TPS7A6333-Q1.

    And could you please set the output capacitor = 10uF (ceramic) only?
    You don't need to consider electrolytic capacitor.

    Best regards,
    Atsushi Yamauchi

  • 0 in reply to Atsushi Yamauchi
    TI__Expert 5675 points
    Hi Yamauchi san,

    I should say, I could only measure the bode plot of TPS7A6301-Q1.
    The reason is, to get the loop frequency gain/phase response(bode plot), we need one injection point to inject one small signal into the control loop. As TPS7A6333-Q1 and TPS7A6350-Q1 are fixed version watchdog LDO, loop is controlled inside the IC, there is no injection point for test. But small signal could be injected into from the FB pin of TPS7A6301-Q1.

    As these devices (TPS7A6301-Q1, TPS7A6333-Q1 and TPS7A6350-Q1) are in the same family, loop frequency gain/phase response should be similar.

    Best regards,
    Jason Liu
  • 0 in reply to Jason. Liu
    Genius 4810 points
    Dear Jason-san,

    Thank you for your help.
    It is no problem for the measurement of TPS7A6301-Q1.

    Best regards,
    Atsushi Yamauchi
  • 0 in reply to Atsushi Yamauchi
    TI__Expert 5675 points

    Hi Yamauchi san,

    Below is the bode plot of TPS7A6301-Q1. My test condition is, VIN=14V, VOUT=5V(R1/R2=100k/32.4k), Cout=10uF(ceramic capacitor).

    As this is test on bench with limited devices, the data is for reference only.

    BTW, can you please inform more information about customer's application? Why customer is concerning about the bode plot?

    Best regards,

    Jason Liu

  • 0 in reply to Jason. Liu
    Genius 4810 points
    Dear Jason-san,

    Thank you for your quick response.
    I think the current range is OK. Is it correct?
    (The phase margin is over 45 degree at 0dB.)
    And why are there the difference between 1mA and other current?

    The application is NFC for Automotive. They want the evidence the operation is stable.

    Best regards,
    Atsushi Yamauchi
  • 0 in reply to Atsushi Yamauchi
    TI__Expert 5675 points
    Hi Yamauchi san,

    Yes, the phase margin is over 45 degree at 0dB.

    For the difference between 1mA and other current condition, the reason could be the limitation of the test equipment.
    When Iout is 1mA, but the injected small AC signal from the test equipment would also generate current as much as several amperes, this could affect the results heavily.
    Customer could take the results of 50mA and 100mA for reference, however, I still put all the data in the figure.

    Best regards,
    Jason Liu