Can the ESP32S3 use a 40M active crystal oscillator?
Posted: Tue Sep 30, 2025 6:27 am
The schematic design document for the ESP32S2 introduces the active crystal circuit: If an active crystal is to be used, connect the clock output of the active crystal to the XTAL_P terminal on the chip side through an AC coupling capacitor (around 50 pF), and leave the XTAL_N floating. Now I am using the ESP32S3, and the clock buffer chip provides a 3.3V 40M CMOS clock, which is AC-coupled to the P terminal via a 47pF capacitor, with the N terminal floating. However, the chip seems not to be working properly.