LMR14020-Q1: Influence of spread spectrum for audible noise

Kuramochi Tadahiko

Guru 28715 points

Part Number: LMR14020-Q1

Hi,

My customer is evaluating LMR1402-Q1 w/wo spread spectrum(SS).

They can hear audible noise from the only board with SS.

Does SS affect to audible noise?

If it is yes, is there any effective workaround?

(Is it to change external components such as inductor ,capacitor)?

Best Regards,

Kuramochi

over 7 years ago

0 Vental Mao over 7 years ago

TI__Expert 5745 points

What's the switching frequency? And is the board working under the PFM?

0 Kuramochi Tadahiko over 7 years ago in reply to Vental Mao

Guru 28715 points

Hi Mao-san,

I'm confirming above condition to the customer.

Should we select inductor and capacitor corresponded audible noise when using device with spread spectrum?

Best Regards,
Kuramochi

0 Vental Mao over 7 years ago in reply to Kuramochi Tadahiko

TI__Expert 5745 points

If the board work under the PFM, the switching frequency will be during the audio band.

0 Kuramochi Tadahiko over 7 years ago in reply to Vental Mao

Guru 28715 points

Mao-san,

Thank you for your advice.
I got it.

Best Regards,
Kuramochi

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LMR14020-Q1: Influence of spread spectrum for audible noise