Burr-Brown PCM4222 data sheet now available

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Boswell

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Apr 29, 2006
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TI's Burr-Brown division has just released the preliminary data sheet for the PCM4222 - a 216KHz (max) 24-bit stereo ADC that was shown at AES.

It looks a very interesting part. It has a choice of digital output formats, although none of which, sadly, is directly S/PDIF compatible. It needs +3.3V and +4.0V (!) power supplies.

As with most of these new parts, I'll be looking at how it could be incorporated into a digitising pre-amp or similar equipment. It's not until you get to the minutiae of the design do you find the features that make a new part difficult to work with.

http://focus.ti.com/lit/ds/symlink/pcm4222.pdf
 
lol - I have enough reports on me dude... :grin:

Just wait until you see the EVM for this part. It's pretty much the same front end as the PCM4202 EVM.

The EVM gets 123dB 'A weighted' without a sweat.

Mwahahahah - World Domination... coming up!
 
use a device like the DIT4096.

The DIT4096 can be used in a hardware mode - so that high or low voltage on the pins can be used to set various modes (like frequency etc)

If you want to see how to hook up an I2S source (ADC) to a DIT4096 or DIT4192 (96KHz and 192KHz capable) then take a look at the EVM schematic for the PCM4202. The board is pretty much the same in both.

http://focus.ti.com/docs/toolsw/folders/print/pcm4202evm.html

You can see a picture of the board on that page too (there's a link). As you can see, the most complex part of the board is the actual input buffer. (which isn't really that complex). The rest of the board is looked after by DIP switches.
 
I have seen the DIT parts but it was my impression that AES3 wasn't exactly the same as S/Pdif even though most modern S/Pdif receivers can recognize it. AES3 has more information bits doesn't it?
 
The DIT parts support both.

SRC4392 Datasheet
The AES3-2003 standard defines a technique for two-channel linear PCM data transmission over 110W shielded twisted-pair cable. The AES-3id document extends the AES3 interface to applications employing 75W coaxial cable connections. In addition, consumer transmission variants, such as those defined by the S/PDIF, IEC 60958, and CP-1201 standards, utilize the same encoding techniques but with different physical interfaces or transmission media. Channel status data definitions also vary between professional and consumer interface
implementations.
Click to expand...

http://en.wikipedia.org/wiki/SPDIF
S/PDIF remained identical at the protocol level, but changed the physical connectors from XLR to either electrical coaxial RCA jacks or optical TOSLINK, both of which cost less and are easier to use. The cable was also changed from 110 Ω (ohms) impedance balanced twisted pair to the already far more common (and therefore compatible and inexpensive) 75 Ω coaxial cable, using RCA jacks instead of the "BNC" connector found in broadcast television. S/PDIF is, for all intents, a consumer version of the AES/EBU format.
Click to expand...


and finally...
http://en.wikipedia.org/wiki/AES/EBU
The Channel Status Bit in AES/EBU
As stated before there is one channel status bit in each subframe, making a 192 bits word each audio block. This means that there are 192/8 = 24 byte available each audio block. The contents of the channel status bit are completely different between the AES / EBU and the SPDIF. For the AES / EBU, the standard describes in detail how most part of the bits have to be used. Here is only an overview from a higher point of view, as only the aim of the 24 bytes are described:

byte 0: basic control data: it says if the audio is compressed or not, if there is any kind of emphasis, which is the sample rate.
byte 1: it says whether the audio stream is stereo, mono or other their combinations.
byte 2: it indicates the audio word length.
byte 3: it is used only for multichannel applications.
byte 4: it indicates the suitability of the signal as a sampling rate reference.
byte 5: reserved.
bytes 6 - 9 and 10 - 13: these two slots of four bytes each are used to transmit ASCII characters.
bytes 14 - 17: these 4 bytes provide a slot of 32 bit in which there is a sample address incrementing every frame. It is used to number the frames
bytes 18 - 21: as above, but in a different format, as it is relative to the actual time (it starts from zero at midnight)
byte 22: it contains information about the reliability of the audio block.
byte 23: the final byte is a CRC. If it is not received, it means that the transmission was interrupted before the end of the audio block, and so the audio block is ignored.
Click to expand...


So... the only difference is those 24 bits and how they are used.
The digital audio side (which is what you're really looking for) stays the same..

I think :)

Cheers

R
 

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