LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual
UBX-14054794
Production Information
Design-in
Page 44 of 85
2.6.3
Active antenna bias power (LEA-6)
There are two ways to supply the bias voltage to pin
V_ANT
. For Internal supply, the
VCC_RF
output must be
connected to
V_ANT
to supply the antenna with a filtered supply voltage. However, the voltage specification of
the antenna has to match the actual supply voltage of the u-blox 6 Receiver (e.g. 3.0 V).
u-blox 6 Module
GND
RF_IN
GND
Active Antenna
V_ANT
VCC_RF
LNA
R_BIAS
Figure 42: Internal supply Antenna bias voltage (for exact pin orientation see data sheet)
u-blox 6 Module
GND
RF_IN
GND
Active Antenna
V_ANT
VCC_RF
LNA
external
antenna
voltage
supply
R_BIAS
Figure 43: External supplying Antenna bias voltage (for exact pin orientation see data sheet)
Since the bias voltage is fed into the most sensitive part of the receiver, i.e. the RF input, this supply should be
virtually free of noise. Usually, low frequency noise is less critical than digital noise with spurious frequencies with
harmonics up to the GPS/QZSS band of 1.575 GHz and GLONASS band of 1.602 GHz. Therefore, it is not
recommended to use digital supply nets to feed pin
V_ANT
.
An internal switch (under control of the u-blox 6 software) can shut down the supply to the external antenna
whenever it is not needed. This feature helps to reduce power consumption.
2.6.3.1
Short circuit protection
If a reasonably dimensioned series resistor
R_BIAS
is placed in front of pin
V_ANT
, a short circuit situation can
be detected by the baseband processor. If such a situation is detected, the baseband processor will shut down
supply to the antenna. The receiver is by default configured to attempt to reestablish antenna power supply
periodically.
To configure the antenna supervisor use the UBX-CFG-ANT message. For further information refer to the
u-blox 6 Receiver Description including Protocol Specification
