Hi everybody.
I'm working on a personal project of a 2xWM8740 dac with headphone amplifier. I have several digital inputs: USB, OPTICAM and COAX. The USB input is done with a CM6631A and the OPTICAL and COAX are fed into a WM8804. From the CM6631A board and from the WM8804 I have I2S going to each DAC. I'm now using ADG794 to switch between the two sources but I see that the 24MHz signal is degraded (rounded edges and some noise) and I think this is due to the ADG794. The ADG794 is a 300MHz device that has a pretty low RdsON and input capacitance. Is there a better switch that I shoudl use? The DAC works perfectly fine with this setup but I do not like the way the 24MHz clock looks. The 12MHz and the rest of the signals look very good.
Thanks,
Horia
I'm working on a personal project of a 2xWM8740 dac with headphone amplifier. I have several digital inputs: USB, OPTICAM and COAX. The USB input is done with a CM6631A and the OPTICAL and COAX are fed into a WM8804. From the CM6631A board and from the WM8804 I have I2S going to each DAC. I'm now using ADG794 to switch between the two sources but I see that the 24MHz signal is degraded (rounded edges and some noise) and I think this is due to the ADG794. The ADG794 is a 300MHz device that has a pretty low RdsON and input capacitance. Is there a better switch that I shoudl use? The DAC works perfectly fine with this setup but I do not like the way the 24MHz clock looks. The 12MHz and the rest of the signals look very good.
Thanks,
Horia
Yes, I did look at the 74AHC157 and I plan to test it. Good thing is that it is pin to pin compatible 🙂. I will also test the TMUX1574. I'll come back here with the results and maybe a few scope caputres showing the behaviour of the differete switches.
Given the CM6631A and WM8804 are 3.3V devices a 74LVC157 makes a more obvious choice of multiplexer, and faster.