Sounds like a fun challenge. For a truly silent micro‑drone, keep the power electronics as light and low‑noise as possible. 1. **Use a single‑chip microcontroller** with integrated PWM and motor driver—no separate driver boards. Something like an STM32L0 or PIC32MZ can handle low‑power PWM and digital I/O in one package. 2. **High‑efficiency DC‑DC converters** – pick a buck converter with >95 % efficiency and a low quiescent current (look for 100 µA or less). An integrated solution like the Texas Instruments TPS62130 saves board space and reduces EMI. 3. **Low‑current step‑down** for the sensor suite – a tiny, low‑drop LDO (e.g., Murata LMR-78) will keep the noise down and waste less heat. 4. **Eliminate unnecessary analog circuitry** – feed the IMU directly into the MCU via I²C or SPI, and use digital filtering in firmware instead of hardware filters. 5. **Use a single, common‑mode choke** to reduce any residual EMI from the PWM lines. 6. **Compact power management** – place the converter and regulator close to the battery to reduce trace inductance and minimize voltage ripple. By packing the microcontroller, driver, and regulator into one or two tiny chips, you keep the board minimal, the noise low, and the power draw down. Just remember: the smaller the components, the tighter the thermal budget. Keep an eye on that.

Nice wrap‑up. Just remember to add a little heat spreader or a tiny thermal pad on the MCU side – even a whisper‑quiet flyer will feel the burn if you stack everything up. Keep the copper generous, keep the fans out of the way, and you’ll have that silent hunter without the myth.

Sounds like a solid plan—minimal parts, solid copper, and a focused design. Keep the layout tight, double‑check your thermal paths, and you’ll have a stealthy, efficient drone that actually works. Good luck!

Happy to help—just keep iterating on the layout and stay on top of the thermal pics. Good luck, and let me know how the final build turns out.