Hello,
I'm planning to use an STM32WL5X microcontroller in an upcoming project, and I found myself confused on the recommended impedance for external 32MHz oscillators. Please see the attached image for a screenshot from the datasheet.
The datasheet says that the incoming clock signal needs a minimum of 0.4 Vpp, and an absolute max of 1.2 Vpp. Note 1 below the table says that oscillators outputting a 0.8 Vpp signal should have a 220 ohm resistor and 10 pF capacitor put in series before the oscillator input pin. The oscillator input has a minimum input capacitance of about 11 pF.
If the input signal is 0.8 Vpp, and you make a voltage divider as described, the input signal is going to be way less than 0.4 Vpp. How is that supposed to work??
@Peter BENSCHand @HamiltonDC, I found other forum responses from you two on this issue, but I still don't understand the math behind this. How is the input signal wave supposed to be greater than 0.4 Vpp?
