PCM4204 ADC

[mcs]

As discussed in various ADC/DAC threads, I am trying to design an ADC using the TI PCM4204 4-channel ADC.

Here's the preliminary schematic: http://stiftsbogtrykkeriet.dk/~mcs/PCM4204ADC_sch.gif

I have left-out the analog input stages. I have only included the filter caps that should be fitted close to the chip, according to the datasheet.

Any comments, questions or errors?

Best regards,

Mikkel C. Simonsen

 

[Rochey]

Merry Christmas

looks good to me. What i'm waiting for are the gerbers. :grin:

 

[Rochey]

hia Mikkel,

Just a few quick question for you.

Whats the use of R2 (100R) between the serial data out of the device and the connector?

As well as R3? why set the input inpedance of that circuit at 100Kohms? Surely the input impedanceof the 125A is high enough?

Cheers

R

 

[mcs]

[quote author="Rochey"]Whats the use of R2 (100R) between the serial data out of the device and the connector?[/quote]
Termination. The cable impedance is around 100R, so you often use termination resistors top avoid reflections in the cable. I think you'll see the same resistors in the TI schematics... :grin:

As well as R3? why set the input inpedance of that circuit at 100Kohms? Surely the input impedanceof the 125A is high enough?

It's just there to keep the input from floating when no cable is connected. The 125A is there as a 5V to 3.3V translator BTW.

Best regards,

Mikkel C. Simonsen

 

[beginnerdontlaugh]

Hello,
I know that maybe it's too late to post here but according to Mikkel's schematic, how to record audio data in a DAW through a standard USB protocol? Is it that I need some sort of DSP chip?

I am beginner, so please be gentle with me    8)

Thanks,
Gio

 

[gyraf]

You will need the appropriate USB drivers for whatever system you are using.

Not simple at all for a DIY'er.

Jakob E.

 

[beginnerdontlaugh]

You will need the appropriate USB drivers for whatever system you are using.

Not simple at all for a DIY'er.

Jakob E.

Does that mean PCM4204 is programmable?
Do I need some USB transceiver IC or DSP unit?

 

[Rochey]

PCM4204 outputs a pair of PCM outputs, which will need to be input to a S/PDIF or USB Transciever.

I have my eye on, but I have not tested, a unit made by
https://www.minidsp.com/products/usb-audio-interface/ministreamer