“Time flies when you’re having fun. Or are just too busy with things, in general.
It’s been two and a half years since I posted about my Dual Mono AK4490 DAC. That DAC has been built and is in use by at least 6 people, other than myself. All of them have been very satisfied with its performance.
But since then quite some water has passed under the bridge.
Among other things, the AK4493 chip came out, and it was just that much different than the AK4490 that I had to update my design to accommodate it.
Feature-wise it was pretty enticing. It looked more like a limited performance version of the AK4497 than an upgraded version of the AK4490. So I had to try it out.
Since I was going to update the PCB design, I thought I might as well improve on as much as I could. So, the new board would:
Include a new reclocking solution. I went for the best specc’ed chip out there, the famous Potato Semi PO74G374A. One chip would take care of the all of the I2S lines for both DAC chips.
Add a couple of external 1.8V DVDD power supplies.
Make some optimization of the LT3042 local regulators’ layout, in order to accommodate larger package capacitors (1206) where it would make most sense.
Give access to the zero-detect lines of one of the dac chips. These pins could be used to easily implement auto muting of the output stage.
Give access to the Enable pin of the Si570/Si544. The use of this Enable pin will be explained later.
In addition I would use the then new Si544 programmable oscillator, offering improved performance over the Si570. This did not require any changes to the pcb.”