PCM2704C: Vout coupling capcitor

na na78

Guru 16770 points

Part Number: PCM2704C
Other Parts Discussed in Thread: TAS2521,

We are about to evaluate audio system using PCM2707C and TAS2521 as follows.

According to the datasheet, PCM2704C requires series 100-uF electrolytic capacitors at the Vout line.

1. Are there any reason why electrolytic capacitor is used?

Is it OK to use ceramic one?

2. Are there redundant component in the upper figure?

If so, could you please point it out?

BestRegards

over 7 years ago

0 Diego Melendez over 7 years ago

TI__Guru 57800 points

Hi, Na,

The recommended values for the output filter are set for the best trade-off between cutoff frequency of the filter and pop/click noise suppression, so it is recommended to keep those values. There is an app note for this device where the output filter structure is explained, please refer to section 8 of the attached document.

Best Regards,

-Diego Meléndez López
Audio Applications Engineer

0 na na78 over 7 years ago in reply to Diego Melendez

Guru 16770 points

Hi Diego

Thank you for your advice, but I could not see the attached document.

Could you check it again?

And we need the input impedance of TAS2521 for calculation of proper cutoff frequency.

Do you have information?

BestRegards

0 Diego Melendez over 7 years ago in reply to na na78

TI__Guru 57800 points

Hi, Na,

I have attached the file again, please let me know if this time works. About the TAS2521, I'll ask my colleague about it.

Regards,

-Diego Meléndez López
Audio Applications Engineer

Application_Note_USBCodecs.pdf

0 Ivan Salazar over 7 years ago in reply to Diego Melendez

TI__Guru** 102755 points

Hi Na,

Regarding TAS2521 input impedance I've got result around 7kOhm.

Best regards,
-Ivan Salazar
Audio Applications Engineer - Low Power Audio and Actuators

Audio

Audio forum

PCM2704C: Vout coupling capcitor