NINA-B1 series - System integration manual
UBX-15026175 - R16
System description
Page 13 of 63
C1-Public
Analog pin options
The following table shows the supported connections of the analog functions.
☞
An analog pin may not be simultaneously connected to multiple functions.
Table 6: Possible uses of analog pin
1.9
Antenna interfaces
☞
The antenna interface is different for each module variant in the NINA-B1 series.
1.9.1
Antenna pin – NINA-B111
NINA-B111 is equipped with an RF pin. The pin has a nominal characteristic impedance of 50
Ω
and
must be connected to the antenna through a 50
Ω
transmission line. This allows the reception of radio
frequency (RF) signals in the 2.4 GHz frequency band.
For the best electrical performance and overall module functionality, choose an antenna with optimal
radiating characteristics. Use an internal antenna integrated on the application board, or an external
antenna that is connected to the application board through a proper 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.
Antenna matching
The antenna return loss should be as good as possible across the entire band when the system is
operational to provide optimal performance. The enclosure, shields, components, and surrounding
environment impact the return loss seen at the antenna port. Matching components are often
required to re-tune the antenna to bring the return loss within an acceptable range.
It is difficult to predict the actual matching values for the antenna in the final form factor. Therefore,
it is a good practice to have a placeholder in the circuit with a “pi” network, with two shunt components
and a series component in the middle. This arrangement allows maximum flexibility when adjusting
the tuning to match the antenna feed.
Approved antenna designs
NINA-B1 modules come with a pre-certified design that can be used to save costs and time during the
certification process. To take advantage of this service, the customer is required to implement
antenna layout according to u-blox reference designs. The reference design is described in
Appendix
The designer integrating a u-blox reference design into an end-product is solely responsible for the
unintentional emission levels produced by the end-product.
The module may be integrated with other antennas. In this case, the OEM installer must certify his
design with respective regulatory agencies.
Analog function
Connects to
ADC single-ended input
Any analog pin or VCC
ADC differential input
Any analog pin or VCC pair
Comparator IN+
Any analog pin
Comparator IN-
Pin 24 or 25, VCC, 1.2 V, 1.8 V, 2.4 V
Low-power comparator IN+
Any analog pin
Low-power comparator IN-
Pin 24 or 25, 1/16 to 15/16 VCC in steps of 1/16 VCC
