SI4706-D50 Datasheet, PDF (22/36 Pages) Silicon Laboratories – HIGH-PERFORMANCE FM AND RDS/RBDS RECEIVER

Si4706-D50
4.12. Embedded Antenna Support
The Si4706 is the first FM receiver to support the fast
growing trend to integrate the FM receiver antenna into
the device enclosure. The chip is designed with this
function in mind from the outset, with multiple
international patents pending, thus it is superior to many
other options in price, board space, and performance.
Testing indicates that, when using Silicon Laboratories'
patented techniques, embedded antenna performance
can be very similar in many key metrics to a standard
half-wavelength antenna. Refer to “AN383: Si47xx
Antenna, Schematic, Layout, And Design Guidelines”
for additional details on the implementation of support
for an embedded antenna.
Figure 12 shows a conceptual block diagram of the
Si4706 architecture used to support the embedded
antenna. The half-wavelength FM receive antenna is
therefore optional. Host software can detect the
presence of an external antenna and switch between
the embedded antenna if desired.
Half-wavelength
antenna
FMI
Integrated
antenna
LPI
RFGND
LNA
AGC
Si4706
Figure 12. Conceptual Block Diagram of the Si4706 Embedded Antenna Support
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Rev. 1.0