V1.2 – May-11
User’s Manual
Page 32 of 37
10.7 Antenna Status Adaptation
This chapter shall give assistance in designing a circuit for detecting if an active
antenna is connected to the module. The information about the antenna status can
be derived from the ANTSTAT signal generated by this circuit. The examples use
values for components that roughly result in the following ANTSTAT output:
•
Logic low when:
Iant < 9mA
•
Logic high when:
9mA > Iant < 16mA
•
Logic low when:
Iant > 16mA
10.7.1 Antenna Sensor
The following circuit is a proposal on how you can feed an antenna with 3.3V and
provide an output for the ANTSTAT pin. The value of the components may need an
adaptation in the final application. For example, the input current of the chosen
comparator goes into that equation. The thresholds defined in this circuit are quite
close to the ones described above. Their value is determined by resistors R4, R5,
and R3.
We strongly recommend simulating and testing the GPS receiver integrated in your
product design before implementing the finalized product in the appropriate market
application.
Figure 13: Application note: Antenna sensor adaptation
