NXP Semiconductors FREESCALE MC13192, Reference Manual, Page: 19 / 34

MC13192EVB Reference Manual, Rev. 1.2
Freescale Semiconductor 3-1
Chapter 3
RF Front End
The MC13192EVB is designed to show a high performance, small form factor solution interfacing to a
single antenna. A built in, high performance, PCB antenna enables the design to be evaluated as-is, while
an SMA connector allows for easy RF testing and evaluation of other antenna designs.
Other reference designs demonstrate low cost solutions, integrated antenna designs, and the lowest Bill of
Material (BOM) count possible.
Figure 3-1. MC13191/MC13192 Simplified Block Diagram
Two baluns transform the balanced input and output to a 50 Ohm unbalanced signal. This allows for easy
RF measurements and interfacing to a lot of different antennas, including chip antennas.
An RX/TX switch is included to allow for a single antenna solution. This allows for the smallest design
possible, and the switch is usually cheaper than using two antennas. The switch can be left out if a dual
antenna design is possible.
A simple band pass filter is added to reduce harmonics and provide some RX filtering. It also provides
protection against ESD discharges.
A solder switch selects between the default built-in F-antenna or the SMA connector.
The F-antenna provides good broadband matching and good efficiency, especially compared to size and
cost. Stand offs at least 1 cm high should be mounted on the PCB if placed close to a metallic surface.
Otherwise RF performance will be degraded due to antenna detuning.
Provisions for an optional LNA have been added for those applications that require optimum range.
MC13191/13192
LNA
PA
PA bias
200:50
balun
200:50
balun
Switch
Band
Pass
filter
Optional LNA