• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 31 subscribers
  • Views 129 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.

TAS6422E-Q1: Question about the value of inductor

Chase Jeong
Genius 5000 points
Part Number: TAS6422E-Q1

Dear TI experts,

My customer now tests their own PCB with TAS6422E-Q1.

First they applied 3.3uH for the inductors below. (L38, L39, L40, L41)

They found that there is a sine wave with some noise, and they changed the value of inductors from 3.3uH to 10uH. then the sine wave is much more clear.

(Yellow waveform is applying 10uH, cyan waveform is applying 3.3uH.)

 - Is it ok to use 10uH in this situation?

 - What is difference between 3.3uH and 10uH?

And I have one more question.

  - There are different inductor value between datasheet and EVM schematic. which one is right?

Best regards,

Chase

  • 0
    TI__Mastermind 34480 points

    Hi Chase

    Chase Jeong said:
    They found that there is a sine wave with some noise, and they changed the value of inductors from 3.3uH to 10uH. then the sine wave is much more clear.

    May I ask that are we testing with open load? This small oscillation possibly happens at open load, the frequency is the resonant of the LC filter.

    Chase Jeong said:

     - Is it ok to use 10uH in this situation?

     - What is difference between 3.3uH and 10uH?

    No problem to use 10uH, the cost and the inductor size would be the most challenge.

    Chase Jeong said:
    - There are different inductor value between datasheet and EVM schematic. which one is right?

    I think you mean the BST cap. Originally it's designed with 2.2uF, but too many customer complains, the datasheet changes to 1uF. No problem to use 1uF. The efficiency with 1uF possibly a little smaller than 2.2uF, maybe 1 or 2 percentage difference.