MAX-8 / MAX-M8 - Hardware Integration Manual
UBX-15030059 - R05
Design
Page 13 of 31
Production Information
The
LNA_EN
pin (LNA enable) can be used to turn on and off an optional external LNA in power save
mode in on/off operation.
The
VCC_RF
output can be used to supply the LNA with a filtered supply voltage.
☞
A standard GNSS LNA has enough bandwidth to amplify GPS/GLONASS/BeiDou signals.
Figure 8: MAX-M8W Module design with passive antenna and an external LNA and SAW (for exact pin orientation see the
MAX-M8 Data Sheet
[2])
2.4.2
Antenna design with active antenna
Active antennas have an integrated low-noise amplifier. Active antennas require a power supply that
will contribute to the total budget of GNSS system power consumption, with typically an additional
5 to 20 mA.
If the supply voltage of the MAX-8 / M8 receivers matches the supply voltage of the antenna (e.g. 3.0
V), use the filtered supply voltage
available at pin
VCC_RF
as shown in Figure 9.
Active antenna design using VCC_RF pin to supply the active antenna
Figure 9: MAX-8C/Q and M8C/Q active antenna design, external supply from VCC_RF (for exact pin orientation see the
MAX-
8 Data Sheet
[1]
and
MAX-M8 Data Sheet
[2])
For the MAX-M8W active antenna design with external supply from VCC_RF, see Figure 11.
In case the
VCC_RF
voltage does not match with the supply voltage of the active antenna, use a
filtered external supply as shown in Figure 10.
