ANNA-B112 - System integration manual
UBX-18009821 - R09
System description
Page 17 of 66
C1-Public
Comparator
The comparator compares voltages from any analog pin with different references as shown in Table
11. It supports full 0 V to VCC input range and can generate different software events to the rest of
the system.
Low power comparator
The low-power comparator operates in the same way as the normal comparator, with reduced
functionality. It can be used during system OFF modes as a wake-up source.
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 11: Possible uses of analog pin
Antenna interface
The ANNA-B112 is equipped with an integrated antenna in the module. Depending on how the RF pins
are connected, the internal antenna can be bypassed and an external antenna can be used instead.
Table 12 describes how the RF related pins shall be connected for each antenna solution.
*Connect to GND for better layout, not critical for function
Table 12: ANNA-B112 Antenna options
1.10.1
Integrated antenna
The ANNA-B112 is equipped with a certified integrated antenna in the module. To take advantage of
the ANNA-B112 certification, the customer is required to implement the specific ground plane design
according to u-blox reference design. The reference design is described in Appendix B.
1.10.2
Antenna pin (external antenna)
The ANNA-B112 is equipped with an RF pin. The RF pin has a nominal characteristic impedance of 50
Ω
and must be connected to the antenna through a 50
Ω
transmission line to allow reception of radio
frequency (RF) signals in the 2.4 GHz frequency band.
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
External antenna
Integrated antenna module placed
in the corner of the PCB
Integrated antenna module
placed on the side of the PCB
Pin 1 – ANT_PCB
GND*
GND pattern
NC
Pin 2 – ANT_GND
GND
NC
GND pattern
Pin 3 – ANT_GND
GND
NC
GND pattern
Pin 5 – ANT_INT
GND*
Connect to pin 6 – ANT
Connect to pin 6 – ANT
Pin 6 - ANT
Connect to external antenna Connect to pin 5 – ANT_INT
Connect to pin 5 – ANT_INT
