Im prototyping audio router / volume control board using adg2128 and multiple mcp4651 digital pots, all controling by stm32f103r m/c.
My adg2128 schematic is very similar to eval board, single power supply 5v or 12v for avdd (tried both) and 3.3v for vl, avss tied to gnd, inputs/outputs for adg2128 are pulled to gnd with 10k
First issue i found is a readback bug.
If you are writing 0x1 value to X0, first readback will return 0x1 and all next readbacks will return 0, but X0 will still be connected to Y0, so it's a readback bug, not switching issue. But it's not as important for me, only simple code workaround.
Second and much more important issue - after ~ 0.1v im getting some kind of clipping of signal from that input and i can hear it at any outputs (for my case Y are inputs, X are outputs)
For example, i have "heavy" signal at Y0/Y1, my X0/X1 output connected to Y2/Y3 but i can hear clipping from Y0/Y1. Decreasing input level to some lower level solving issue at all (only very small and not clipped crosstalk exists).
Ive tried to replace avdd source from 5v to 12v but nothing changes, its' clipping and cross talking clipping artefacts to other channels.
What i did wrong?
Here is an issue example recording
last few secd with music after a switching from empty input to "heavy" input
ive checked with oscilloscope
here is 315hz when input is connected to testing output
and after switching to empty input
I'm looking into this. In the meantime, can you send on the schematic of the board?
Thanks for the feedback
Can you also send a scope shot showing the digital controls and the switch output? We'd like to check if the digital controls provide correct timing and matches the switch output.
Unfortunately i dont have a multichannel oscilloscope to record it with analog signal. I can use a logic analyzer and feed inputs with square generator if you wish to record switching sequences but im sure switching works flawlessly.