PCM4204: Question regarding unused channels

Brian Antheunisse

Part Number: PCM4204

My customer will only use channels 1 and 2 on a PCM4204 in their design. The Channel 3 and 4 are not used. Can we leave Vin3+, Vin3-, Vin4+, Vin4-, and SDOUT2 unconnected? How about Vref34+, Vref34-, Vcom34, AGND3?

Thanks,

Brian

over 8 years ago

0 Diego Melendez over 8 years ago

TI__Guru 57800 points

Hi, Brian,

The unused inputs can be AC coupled to ground. I'll check about the other pins and will get back to you as soon as possible.

Best Regards,

-Diego Meléndez López
Audio Applications Engineer

0 Brian Antheunisse over 8 years ago in reply to Diego Melendez

TI__Expert 5265 points

Hi Diego,

Any comment on the other pins?

Thanks,
Brian

0 Diego Melendez over 8 years ago in reply to Brian Antheunisse

TI__Guru 57800 points

Hi, Brian,

About the other pins, SDOUT2 can be left disconnected, VREF+ should remain connected to the decoupling capacitor and VREF- to ground. VCOM should keep the decoupling capacitor but can be disconnected from the buffer Op-Amp. AGND should remain connected to GND.

Best Regards,

-Diego Meléndez López
Audio Applications Engineer

0 Brian Antheunisse over 8 years ago in reply to Diego Melendez

TI__Expert 5265 points

Thanks!

What is the ideal capacitance for AC coupling the unused inputs to ground? The PCM4204 has LRCK running at 48.8KHz and BCK running at 64 x LRCK.

Thanks,
Brian

0 Diego Melendez over 8 years ago in reply to Brian Antheunisse

TI__Guru 57800 points

Hi, Brian,

In general there is no recommended value for the AC decoupling cap, for the specific case of the PCM4204, you could start with 4.7µF.

Best Regards,

-Diego Meléndez López
Audio Applications Engineer

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PCM4204: Question regarding unused channels