NEO-M8U - Hardware Integration Manual
UBX-15016700 - R07
Design
Page 13 of 28
Production Information
Figure 7 shows a design using an external LNA and SAW to increase the sensitivity for best
performance with passive antenna. For exact pin orientation, see the
NEO-M8U Data Sheet [1].
Figure 7: Module design with passive antenna and an external LNA and SAW
The
LNA_EN
pin (LNA enable) can be used to turn on and off an optional external LNA.
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.
2.4.2
Active antenna design
An active antenna makes use of an integrated low-noise amplifier, which requires a power supply that
will contribute to the total GNSS system power consumption budget with additional 5 to 20 mA
typically.
If the supply voltage of the NEO-M8U module matches the supply voltage of the active antenna (e.g.
3.0 V), use the filtered supply voltage
available at pin
VCC_RF
as shown in Figure 8. For exact pin
orientation, see the
NEO-M8U Data Sheet [1].
Active antenna design using VCC_RF pin to supply the active antenna
Figure 8: Active antenna design, external supply from VCC_RF
If the
VCC_RF
voltage does not match with the supply voltage of the active antenna, use a filtered
external supply as shown in Figure 9.
For exact pin orientation, see the
NEO-M8U Data Sheet [1].
