Help on buffering microphone board circuit design

Thread Starter


Joined Mar 26, 2018
Dear All About Circuits Members,

i recently designed a small Buffering Microphone for an upcoming research project. The files use the Kicad nightly build.
The Project has the following key components and strategies:
  • Shared Power data line for all boards via RS485 on an THVD8010 IC
  • SPW0690LM4H as Mems microphone
  • STM32L422TBY as Micrcontroller
  • APS6404L-SQRH-ZR as short term memory

The measurment is thought to run as follows
  1. Setup to all microphones via RS485
  2. Set microphone to trigger ready mode via RS485
  3. Trigger all micrphones via RS485, or Flashlight or Pulse on powerline (depends on what is fastest and safest)
  4. Buffer Data for around 1s-10s
  5. Recall all Data one by one

Because we want to make 250 of those microphones i want to be absolutely sure everything works.
Curently i am working on an evaluation Board to pre test the system but i would appreciate every input to the design and concept.
I allready talked to a manufacturer who said there are no problems manufacturing wise on the pcb.

Do i realy need the full bridge recifier shown in THVD8010s data sheet for typical application? I currently intend to use 5V transmission line power voltage.Circuit_Designn.jpg

I am looking forward to any suggestions.



Joined Apr 4, 2016
The THVD8010 is for signalling over an AC power line. So the bridge rectifier is for AC to DC power conversion.
Are you signalling over an AC power line? Or are you using a separate pair for the RS485 signalling?