AN851 Datasheet, PDF (13/25 Pages) Silicon Laboratories – Si468X SCHEMATICS AND LAYOUT GUIDE

AN851
5.5. Ferrite Loop Antenna Design Checklist
 Place the chip as close as possible to the ferrite loop antenna feedline to minimize parasitic capacitance and
the possibility of noise coupling.
 Place the ferrite loop stick antenna away from any sources of interference and even away from the I/O signals
of the Si468x. Please make sure that the AM antenna is as far away as possible from circuits that switch at a
rate which falls in the AM band (520–1720 kHz).
 Place optional component D1 if the antenna is exposed.
 Select ESD diode D1 with minimum capacitance.
 Do Not Place any ground plane under the ferrite loop stick antenna if the ferrite loop stick antenna is mounted
on the PCB. The recommended ground separation is 1/4 inch or the width of the ferrite.
Rev. 0.2
13