ESP32 Forum

We have a custom ESP32 board and we're seeing periodic current spikes (thin blue lines on attached image) to about 400mA. This seems to be related to WiFi operation as it doesn't happen if WiFi is off. They are very short so we suspect it's just an artifact of WiFi radio turning on. Has anyone experienced this before?

Yes, this is most likely the WiFi calibration, which is known to generate a spike like that. It's the reason we advise people to use at least a 500mA-capable power supply in the hardware design guidelines.

ESP_Sprite wrote:Yes, this is most likely the WiFi calibration, which is known to generate a spike like that. It's the reason we advise people to use at least a 500mA-capable power supply in the hardware design guidelines.

Would be great though if rf self test was well documented.

Fyi, just talked to a colleague: I may have recognized the spike wrongly; it's more likely to be a WiFi Tx spike.

How much (low ESR) capacitance do you have on the VCC rail? You should be able to smooth these TX current spikes quite a bit via capacitance.