[kipman725]

Hello if someone has any spare time could they check the attached schematic for a PCM2707 configured as a USB>I2S converter. The converter should be 100mA bus powered, the DOUT is connected to the DIN which should (according to the internet) allow me to verify functionality by using the pin header (with scope/crystal earpiece). I used similar chokes to those used in the alien DAC project although I don't particularly need them as the I2S bus will be isolated everything else should be a values and connections directly from the data sheet. With this circuit as I don't care about separating A/D grounds am I fine making the non chip side ground and just punching a VIA for each gnd connection?

 

[error401]

It looks good to me. Your USB pinout might be wrong, but it depends on the schematic symbol I guess. Normally should be VCC, D-, D+, GND from 1-4.

You may be interested to look at my design for a self powered PCM2707 receiver, it is built and working: http://www.gotroot.ca/~ktims/dump/miniusb.pdf

 

[guzzler]

You need to connect Vcc_L, Vcc_R, and Vcc_P to Vcc if you intend to use the analog outs...

 

[error401]

Quote:

Originally Posted by guzzler /img/forum/go_quote.gif You need to connect Vcc_L, Vcc_R, and Vcc_P to Vcc if you intend to use the analog outs...

In bus powered mode, they are powered by the internal 3.3V regulator so that's not necessary. Anyway, it sounds like he just wants I2S out.

 

[kipman725]

The USB pinout was provided by sparkfun and is verified as working by them for the USB port I plan to use so will hopefully work (I will have to send them an annoyed email if it's incorrect!). I also interpreted the schematic as using its internal regulator in bus powered mode . The actual DAC I think will be a differential current mode output one as they have the best performance figures. I have had a look at your schematic error401 and am wondering is there any benefit from using a separate supply for a purely digital circuit?* also TI should make a pure USB>I2C chip as that what the 2707 gets used for most of the time and it wastes space with all that extra circuitry!

*the receiver uses internal PLL's so supply fluctuation causing phase noise should be damped.

 

[error401]

I don't think so, it just seemed like the right way to do it when I had another power supply available.

 

[kiranp]

I had some doubts on the design u had attached... Why is the JP1 used ???? and why you need the VOUTR and VOUTL to a jumper...

How is the clock values on I2S pins are calculated???

In my design i have dis connected the VCOM , VOUTR and VOUTL is there any particular reason for connecting the VCOM to GND???

Please give ur views..

 

[cobaltmute]

JP1 is the audio out.  Obviously an optional part of the design, but there if you wanted to do something with it.
 
I2S clock is 256fs (as per datasheet)
 
If you are just worried about outputting I2S, there are more parts you can remove.

 

[kiranp]

Cobaltmute,
Thanks for the information , i am basically into just I2S output so which all can i remove???
 
Thank you

 

[cobaltmute]

The answer to your question is extremely easy to find with Google.

 

[kiranp]

May i please know why the line FUNC3 is connected to DOUT????? 
 
 
Specs given in tha PCM2707 data sheet

---

 FUNC3 4 I HID key state input (play/pause), active HIGH (FSEL = 1). I2S data input (FSEL = 0)
 
And regarding the HOST pin , for bus powered should that pin be unconnected or connected to VCC in parallel to ground????
 
Please do clarify