Need help using analog multiplexer with DAC setup (signal switching issue)

[Daniel DSouza]

Hi everyone,

I’m currently working on a small project where I need to handle multiple analog signals and route them into a DAC setup for testing and comparison. The idea is to switch between different analog inputs (sensors / signal sources) and feed them into a single processing chain.

To achieve this, I started using a 16-channel analog/digital multiplexer breakout (Hardware I used "click here" ), but I’m running into a few issues that I’m not entirely sure how to debug.

Here’s what I’m facing:

• When switching channels, I’m seeing slight signal instability / noise before it settles
• Some channels seem to have minor voltage variation compared to others
• I’m not sure if I need buffering (op-amp?) before feeding into the DAC
• There’s also a small delay when switching channels—unsure if that’s expected behavior

My setup is currently:

• Multiple analog inputs → MUX → DAC → processing
• Controlled via a microcontroller (GPIO switching)

What I’d like to understand:

1. Is this kind of noise/settling time normal when using analog multiplexers?
2. Should I be adding a buffer stage between the MUX and DAC?
3. Are there better approaches for handling multiple analog inputs in a DAC-focused setup?
4. Any best practices to reduce cross-talk or signal degradation?

I feel like I might be missing something fundamental in terms of signal conditioning or timing.

Would really appreciate any guidance or suggestions from people who’ve worked on similar setups

 

[phofman]

Do you mean DAC or ADC?

That mux chip has THD at 4Vpp signal -66dB with 10k load. Will that be enough for your use case?