Microsemi IGLOO2 - 6 Appendix: Special Layout Guidelines - Crystal Oscillator; Figure 86 Layout of the Crystal Oscillator; Figure 87 Schematics of Crystal Oscillator

Appendix: Special Layout Guidelines - Crystal Oscillator
AC393 Application Note Revision 14.0 90
6 Appendix: Special Layout Guidelines -
Crystal Oscillator
The placement of the crystal needs to be close to the SmartFusion2 or IGLOO2 device. Two capacitors
are to be placed symmetrically around the crystal so that the lengths from the crystal pad to capacitor are
equal, as shown in the following figure. Two traces from crystal to SmartFusion2/IGLOO2 should have
equal lengths.
Figure 86 • Layout of the Crystal Oscillator
Figure 87 • Schematics of Crystal Oscillator
Y
32.768 KHz
AA21
AB21
U1-6
XTLOSC_0
EXTLOSC_0
C
C
30 pF/50 V
30 pF/50 V
SmartFusion2