Proper PCB layout is crucial for crystal oscillator performance. Poor layout can cause start-up issues, frequency instability, excessive EMI, and sensitivity to noise. Following these guidelines ensures optimal operation. Keep crystal traces as short as possible - ideally under 10mm, maximum 20mm. Route traces symmetrically from MCU to crystal. Avoid vias on crystal traces when possible. Keep traces on same layer if feasible. Do not route high-speed signals near crystal traces. Place a solid ground plane under the crystal area. Implement a guard ring around crystal pads connected to ground. Keep ground plane continuous under crystal - avoid splits. Connect guard ring to ground with multiple vias. Place crystal as close as possible to MCU oscillator pins. Place load capacitors immediately adjacent to crystal. Keep other components away from crystal area. Orient crystal to minimize trace length. Minimize loop area formed by crystal and traces. Use ground stitching vias around crystal perimeter. Consider shielding can for sensitive applications. Keep crystal away from RF circuits and antennas. Following these layout guidelines prevents most crystal-related issues. For critical applications, consider using YXC's layout review service before PCB fabrication.