ANNA-B4 series - System integration manual
UBX-21000517 - R03
Contents
Page 13 of 74
C1-Public
⚠
When integrating the u-blox reference design into an end-product, the application designer is
solely responsible for any unintentional emission levels produced by the end-product.
ANNA-B4 integrated antenna
☞
ANNA-B4 is pre-certified with the integrated antenna. To take advantage of this certification, the
module must be integrated in strict accordance with the
ANNA-B4 Antenna reference design
When including ANNA-B4 with an integrated antenna into the application design, the reference
design must be followed precisely to reach full radiated performance. The reference design defines
where to position ANNA on the main PCB and describes how to route the counterpoise antenna trace.
Although an integrated antenna can be placed in either the corner or along the edge of the application
board, a corner location offers slightly better antenna performance.
Antenna connected to the antenna pin
This section describes the integration of any antenna connected to the RF pin, external antenna, or
integrated antenna on the main PCB.
ANNA-B4 is equipped with an RF pin for connection of an antenna when the antenna integrated in
ANNA-B4 is not the preferred antenna option. The RF pin has a nominal characteristic impedance of
50
Ω
and must be connected to the antenna through a 50
Ω
transmission to reach full performance.
In this way, the transmission of incoming and outgoing radio frequency (RF) signals is optimized in
the 2.4 GHz frequency band.
Choose an antenna with optimal radiating characteristics for the best electrical performance and
overall module functionality. Use either an internal antenna integrated on the main PCB or an external
antenna connected to the main PCB through a 50
Ω
connector.
When using an external antenna, the PCB-to-RF cable transition must be implemented using either a
suitable 50
Ω
connector or an RF-signal solder pad (including GND) that is optimized for 50
Ω
characteristic impedance.
2.2.2.1
Approved antenna pin designs
ANNA-B4 module is pre-certified together with external antennas. The external antenna is in this
design connected to the RF pin via a U.FL connector. The connection between the RF pin and U.FL
connector is routed with a 50 ohm transmission line. It is advised to implement this reference design
in the application product to save costs and time during the certification process when implementing
an external antenna. See also the
This reference design is described in Appendix
The module may be integrated with other antennas. In which case, the OEM installer must certify his
design with respective regulatory agencies.
2.3
Module reset
ANNA-B4 series is reset by applying a low level on the
RESET_N
input pin, which is normally set high
with an internal pull-up. A low logic level on this pin initiates
an “external” or “hardware” reset of the
module. The prevailing parameter settings at the time of the reset are not saved in the non-volatile
memory of the module and a proper network detach is not performed.
2.4
Internal temperature sensor
The radio chip in the ANNA-B4 series module contains a temperature sensor that is primarily used for
over-temperature and under-temperature shutdown.