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TPS56628: Recommended Inductor value range

K. Sasaki14
Guru 10200 points
Part Number: TPS56628

Can we use lower than 1uH inductor for TPS56628 1.05Vout circuit to improve transient response?

I understand there is recommended L value 1uH to 4.7uH.

I think it is possible if L x Cout value is within range of datasheet Table1. So we should increase Cout value if we reduce L value.

Do you have any concern?

Best Regards,
Kohei Sasaki

  • 0
    TI__Mastermind 27470 points
    Hi
    I think it should be OK for choosing 1uH.
    May need not only check the stable Switch node but also need to verify the circuit stability by large transient from light load to full load by quick slew rate(defined by practical system reqirument) , if any abnormal osillation happend on Vo, it may indicated the L,C combination is not proper. if Vo transient looks fine, it means L,C is OK for system static and dynamic requriment.

    Need verify the whole input range and temp range for meet the system requirment .

    thanks

    Daniel Li
  • 0 in reply to Daniel Li14
    Guru 10200 points
    Daniel-san,

    Thank you for your reply.
    When we select lower 1uH (ex; 0.68uH or 0.47uH) inductor, can we use it if we confirm normal transient response waveform or Bode plot?
    Is there no problem to use out of range LC value of recommended component value table if we confirm normal transient response waveform or Bode plot?

    Best Regards,
    Kohei Sasaki
  • 0 in reply to K. Sasaki14
    TI__Expert 8245 points
    Hi,

    We cannot guarantee values out of the recommended range, inductor influences not only transient response but also current protection, start-up...You may need to verify what matters in your system before using a lower inductor. Thanks.