How do I recognize an ADAU1452-150?

I'm looking to buy a cheap Aliexpress/eBay ADAU1452 board to learn more about the Analog family of DSPs.

As usual, browsing the seller's description, there is some weirdness that hopefully can be explained by a game of telephone in multiple languages resulting in actual information loss.

One of the puzzling pieces is that in some of those descriptions, the ADAU1542 seems to only support 96KHz SPDIF, and only the ADAU1466 supports 192KHz. That is contrary to all the datasheet info I could find.According to this post ez.analog.com/.../adau1462-150-pll-and-other-settings, any difference is hidden from the user, and SigmaStudio doesn't have a 1452-150 part

I noticed, though, that there is a half-clock version of the ADAU1542, the ADAU1452WBCPZ150. How would I recognize if the chip on those boards is the full speed or half-speed version, from the markings on the chip? The datasheet doesn't show the SMD chip markings (unlike most datasheets), so it's hard to know what to look for

Is the chip below a 294.912 MHz part or the slower 147.456 MHz part?

  • +1
    •  Analog Employees 
    on Apr 12, 2021 12:52 PM

    Hello robca,

    The marking would say ADAU1452WBCPZ150 so the picture does show a "300MHz" part. We usually round up to 300 or 150 to make it easier to describe. 

    Yes, the ADAU1452 is only rated to 96kHz for SPDIF. The ADAU1466 will get you the 192kHz SPDIF. That was one of the changes we made when we added the ADAU146x family of parts. 

    Yes, SigmaStudio does not have the 1452-150 part because it is so close to the 1452. All you will need to do is watch the number of MIPS usage in the compiler report. It will only have half the MIPS but all of the memory and other resources will be the same. That is why we did not build a new DLL for the part. It was better to have the programmers working on new features and bug fixes. 

    Thanks,

    Dave T

  • Thanks for the prompt reply and confirmation.

    I see that a change to the SPDIF specs happened between revisions:

    REVISION HISTORY

    1/14—Rev. 0 to Rev. A Changed S/PDIF Transceiver and Receiver Maximum Audio Sample Rate from 192 kHz to 96 kHz; Table 9 and Table 10 ...... 9

    10/13—Revision 0: Initial Version

    And tables 9 and 10 do say 96KHz. But the datasheet is still pretty inconsistent. In the S/PDIF interface section (page 66 of the latest datasheet), S/PDIF receiver, it clearly says

    The S/PDIF receiver works at a wide range of sampling frequencies between 18 kHz and 192 kHz.

    Which is the part I read originally and that led me to believe that the table I mentioned might be wrong. So probably the datasheet needs an errata.

    Does the SPDIF receiver work at 192KHz but it's not guaranteed/tested, or is 192KHz not even an option in the 1452? If I want to have a 192KHz S/PDIF source, should I use an external S/PDIF-to-I2S converter instead of trying to use the 1452 input?

  • 0
    •  Analog Employees 
    on Apr 12, 2021 9:04 PM in reply to robca

    Hello robco,

    Yes, as you see by the revision notes we discovered shortly after we released the part that SPDIF did not work well at 192kHz. The clock source internally it was using was not fast enough. This was fixed when we came out with the 146x parts. If I recall correctly, the issue with with the SPDIF receiver and not the transmitter. The decision was to change the specs for both but test the SPDIF output and I think you will find it works. The output does not need to sense bit changes so the timing is easier. 

    The last revision of this datasheet that spans over a page I had done. I spent a long time on it and the editing team spent a long time on this and yet there still are a few things that slipped by. I looked at page 66 and did not see the text you cited. Perhaps my PDF is paged slightly differently but I can see where this could slip by. The editors are also really good at catching error between the features or specs and the text later in the datasheet. 

    So if you need the SPDIF receiver to be at 192kHz then use an external receiver. Keep in mind that the ADAU1462 is a drop in replacement for the ADAU1452. you literally do not need to change anything, not even the DLL in SigmaStudio. Then you will get the 192kHz fs for SPDIF.

    Dave T

  • Thanks again, perfectly clear. And, yes, I have seen that the 1462 is a pin compatible IC (which it's great), but since I plan to buy pre-made boards, it would mean removing the onboard 1452 and replacing it. The replacing part is not hard, but with just an hot air station and my (limited) skills, removing it from a populated board can cause problems. Anyway, I have multiple paths forward, and that's all that matters. Appreciated your patience in explaining all the aspects

    And after checking once more, I realize I must have been looking at an old datasheet (here https://www.analog.com/media/en/technical-documentation/data-sheets/ADAU1452.pdf) and not the latest one here https://www.analog.com/media/en/technical-documentation/data-sheets/ADAU1452_1451_1450.pdf, And that one correctly says 18 to 96. Apologies for implying your review skills were not good enough Flushed. For what is worth, the first link in a Google search for "ADAU1542 datasheet" (no quotes), returns the old datasheet and not the latest one.