So I have dug into the ADAU1966 datasheet and evaluation board manual (applies to ADAU1962 as well).
The datasheet states AVDD is 5V, ranging 4.5V to 5.5V only. The evaluation board has the option to feed AVDD 3.3V or 5V.
As per the last blog post, pin 44 also has different information on datasheet and evaluation board manual. And I don't get the expected CM voltage.
Am I smelling a silicon bug here? Just a guess. It was strange that the ADAU1966 suddenly became unobtanium last year. Analog Devices still say it is in product. Farnell at one point said no longer manufactured. Mouser stocks the "lesser" ADAU1962 (non A) saying life cycle is unclear! Which is no good. Digikey says there are 7000 factory stock of the ADAU1966.
Things are clearer looking at the new ADAU1966A and ADAU1962A. They only allow 3.3V on AVDD, so not directly compatible with the old parts which would annoy any volume manufacturers using the product. (You need us to change voltage regulators as well!? But we already have stock of 5V parts... I can hear them saying).
I shall update my design for the A parts, adjust supply voltages. Quite honestly I cannot be bothered with wasting time where part specs seem plain wrong and inconsistent. Drawback is reduced dynamic range, not sure that's an issue. With current design, it works, you just don't get peak to peak voltages as per the ADAU1966 datasheet. No idea if it effects other performance (THD+N etc).
Finally I was looking to order some AK4458VN parts for the new DAC board, and there is no stock. Digikey will let you order from 1+ quantity on 20 week lead time. Cheap as well £4.36 each up to ten, or £3.90 each for 10+ and so on. Will likely have to try this and just wait.
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An electronics engineer and a long term electronics hobbyist. I like tinkering with stuff and making things.