hi,

During re-design an old board I wish to ask next question.

On our board we use not crystal but Oscillator chip. Its output is connected to XTAL1 pin of MCU. Because there is no crystal, we do not use XTAL2 pin. As we know, XTAL2 is the output of invertor of pin XTAL1. As result, XTAL2 emits the same frequency as the oscillator and due the pin is not connected so it works like an antenna producing high-frequency EMI. I understand that at 30MHz the length of effective half-dipol is about 5 meters and so 5mm cannot produce high level. Anyway our board is for device where even small EMI may cause problems.

Have somebody an idea about it? Does any capacitor/resistor on XTAL2 may decrease this EMI level or should we use hardware shield over the whole board? Or, as last case, maybe am I so paranoic to think about such EMI sources?

Thanks,
Oleg