Pin 11 and pin 17 are the power supply pins for RTC IO and CPU IO respectively, in a voltage range of 3.0 V ~ 3.6 V. We recommend adding a 0.1 μF capacitor close to each power supply pin. When working as an output power supply pin, VDD_SPI (pin 18) mainly powers external SPI flash. We recommend adding a 1 μF filter capacitor between VDD_SPI and ground. When VDD_SPI works as the power supply pin for in-package flash or external 3.3 V flash, the voltage of VDD3P3_CPU should be maintained at 3.0 V or above, to ensure the flash's operation.
Pin 2, pin 3, pin 31, and pin 32 are the analogue power supply pins, working at 3.0 V ~ 3.6 V. Please note that when ESP32-C3 works in transmission (TX) mode, the instantaneous current will be higher and may cause power rail collapse. Therefore, it is highly recommended to add a 10 μF capacitor to the power trace, which can work in conjunction with the 0.1 μF capacitor. In addition, an LC filter circuit needs to be added near pin 2 and pin 3 to suppress high-frequency harmonics. The inductor's rated current is preferably 500 mA or above. Refer to the core circuit schematic and place the appropriate decoupling capacitor near each analogue power pin.
For a single power supply, the recommended voltage is 3.3 V, and the recommended output current is 500 mA or above. We also suggest adding an ESD protection diode at the power entrance.