3.3.5 Matching Network for 2.4 GHz
The BRD4257B Radio Board incorporates a 2.4 GHz matching network which connects the 2.4 GHz TRX pin of the EFR32FG14 to the
one on-board printed inverted-F antenna. The component values have been optimized for the 2.4 GHz band RF performance and cur-
rent consumption with 13 dBm output power.
For a detailed description of the matching network, see Chapter
4.2.2 Description of the 2.4 GHz RF Matching
3.3.6 SMA Connector
To be able to perform conducted measurements or mount external antenna for radiated measurements, range tests etc., Silicon Labs
added an SMA connector to the Radio Board. The connector allows an external 50 Ohm cable or antenna to be connected during de-
sign verification or testing.
3.3.7 UFL Connector
To be able to perform conducted measurements, Silicon Labs added a UFL connector to the Radio Board. The connector allows an
external 50 Ohm cable or antenna to be connected during design verification or testing.
Note:
By default, the output of the matching network is connected to the printed inverted-F antenna by a series component. It can be
connected to the UFL connector as well through a series 0 Ohm resistor, which is not mounted by default. For conducted measure-
ments through the UFL connector, the series component to the antenna should be removed and the 0 Ohm resistor should be mounted
(see Chapter
4.2.2 Description of the 2.4 GHz RF Matching
for further details).
3.3.8 Radio Board Connectors
Two dual-row, 0.05” pitch polarized connectors make up the BRD4257B Radio Board interface to the Wireless Starter Kit Mainboard.
For more information on the pin mapping between the EFR32FG14P233F256GM48 and the Radio Board Connector, refer to Chapter
2.2 Radio Board Connector Pin Associations
.
3.3.9 Inverted-F Antenna
The BRD4257B Radio Board includes a printed inverted-F antenna (IFA) tuned to have close to 50 Ohm impedance at the 2.4 GHz
band.
For detailed description of the antenna, see Chapter
.
3.3.10 Serial Flash
The BRD4257B Radio Board is equipped with an 8 Mbit Macronix MX25R SPI flash that is connected directly to the EFR32FG14 to
support over-the-air (OTA) updates. For additional information on the pin mapping see the schematic of the BRD4257B.
3.3.11 Serial EEPROM
The BRD4257B Radio Board is equipped with a serial I
2
C EEPROM for board identification and to store additional board related infor-
mation.
BRD4257B Reference Manual
Radio Board Block Summary
silabs.com
| Building a more connected world.
Rev. 1.00 | 7
