I am projecting a brushless motor driver that contains a LoRa SX1276 radio and a ESP32-D0WDQ6 chip. The power line then gets really noisy when everything is working. For the RF blocks (SX1276 and ESP32), it needs to be very clean at the 3.3v fixed voltage. There are some power signals on the board, so that the image bellow shows the power tree with it's loads on each branch:
That being said, I have some questions:
- Is there any problem on using the same LDO(ADM7172) to power both the analog chip lines (i.e. ESP32 and SX1276)? This LDO is going to be used exclusively to these two chips, as it's shown above.
- The digital blocks from ESP32 and SX1276 are going to be powered by the "green-one" LDO line, on the diagram above. Add to this, the IMU and the DRV motor driver. Despite this LDO is 1A capable, it is recommended to power multiple ICs with one LDO? The noisy around this configuration is acceptable? (Bellow, the schematics:)
- How GPIOs affect the LDO stability in order to not disturb other chips? Considering the fact that some chips have GPIOs and SPI pins to communicate with the microcontroller, how to prevent oscillations on that LDO that powers the ICs?
Basically my doubts are about how to stabilize the digital and the analog circuitry and when to divide the source of power between this two parts, or even when use the same LDO to power all this pins.
I hope you can give me some ideas, and thanks you guys for sharing the knowledge!!