how hard would it be to make a simple S/PDIF, coax DAC with the TDA1545

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No ideas

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Joined 2024
#1
found an old sony mini system in the bin and in it there was this tda1545 ic(along other usefull components) and im wondering how hard would it be to make a simple spdif/coax dac for my tv(that lacks an anlog output) or a crappy dvd player.
IMG_1097.jpeg

i also professionaly soldered one of the legs back on. it works but it looks a bit ugly.
 
#3
You would have to build a circuit as in figure 1 of the datasheet, http://tech.juaneda.com/download/TDA1545a.pdf , with small series resistors and AC coupling capacitors added at the outputs, and add an S/PDIF receiver IC that can output data in the format of figure 6 of the datasheet, and a regulated supply.

Strangely, the format of figure 6 appears to be right-justified rather than I2S. Philips invented I2S, so you would expect them to use that.

The S/PDIF receiver would also need an application circuit as shown in its datasheet. It is easiest to take one that can be configured without microcontroller, so you don't need to add one.
 
#10
I once modified a Lite DAC-AH (which originally had TDA1543s) to use TDA1545s. But I think that had CS8412, not CS8416. I was rather assuming CS8416 would have a superset of CS8412's functionality but perhaps that's a step too far. Let me check...

<later> You're quite right Marcel, only 24bit L and R justified are available in hardware mode. Whereas CS8412 mode '5' limits the data frame to 16bits. So CS8416 RJ in 24bits might not work fine if the source sends more than 16 valid bits.
 
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#16
MarcelvdG said:
Can you set the CS8416 to 16 bit right justified in hardware mode?
Click to expand...
No. Grr! It'll do left or right justified 24-bit, but not 16 bit. So it'll take some glue logic if the DAC expects 16 bits. It'll also do "direct AES3" but I think that includes data bits and some control bits, so that's not super useful either.

WM8805 will do right justified 16-bit, though. So that could be an option. That chip's now discontinued, but it hasn't been out of production for that long so I bet you can still find them. If the WM8805 can do it, I bet the 8804 can as well. The two chips are identical as far as I can tell, except for the multiple inputs on the 8805.

Tom
 
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