Wifi interfering with analog signals on custom PCB

Thread Starter


Joined Mar 6, 2020

I'm facing an issue regarding the design of my current circuit board. I'm designing a custom PCB with analog circuitry that's aquiring data. This data is send out via Wifi with the ESP32. I want to use the LOLIN Lite Board as ESP-Board. Therefore I have to connect POWER Pins and SPI-Signals from the analog board to the ESP Board.

Option 1 : mouting the analog board as a shield. My application requires small height (< 1 cm) so I could use small pin headers or solder the male pin headers from the ESP Board directly to the analog module. Mounting the analog modul directly above the ESP Board might cause problems with the wifi signals interfering with the sensitive analog signals. I could use a four layer board for shielding and also add filters/ferrits in the analog signal path, but I'm lacking experience to tell if that would be sufficient. Also I use differential signaling on all analog paths.

Option 2 : use some sort of shielded wires to connect the ESP-Board pins to the analog module. At the side of analog-board I'm basically free to use any connector, but with the ESP-Board I'm forced the use standard 2.54 headers. At first I was thinking about using some rectangular pin headers and crimp dupont connectors on ribbon cable. But since I need to transmit an SPI-CLK of atleast 40 MHz this might not work. It's also problematic that I need to connect to both header rows on the LOLIN Board because GND is located on the 2nd row.

Do you have comments on either option or any idea for a better solution. I appreciate any help!

Regards Dave


Joined Jan 27, 2019
No it's just a concern that I have designing the board.
Premature optimization is the bane of design. If you consider it a potential problem you either need to test empirically or calculate the probability. Mitigating a problem that may not exist can not only increase costs but it can introduce unintended side effects that will require mitigation on their own, for no reason.

Testing if possible is best. Failing that, calculating/measuring signal levels, and comparing frequencies can help decide if there is a need for more.