Neoway N720 - Figure 3-6 Power Supply Reference for Active Antenna

N720 Hardware User Guide
Copyright © Neoway Technology Co., Ltd 39
Common active antenna requires 3.3 V to 5 V power supply. Though the active antenna has a low power
consumption, it requires stable and clean power supply. It is recommended that high-performance LDO is
used to supply power for the antenna through a 100 nH inductance, as shown in Figure 3-6.
Figure 3-6 Power supply reference for active antenna
LNA
Active
Antenna
N720
LDO
PWR_input
22 uF
33 pF
100 nH
33 pF
50Ω impedance line
It is recommended that an ESD protection diode is added to the antenna interface in an environment with
great electromagnetic interference and other applications with bad ESD. The ESD protection diode must
have ultra-low capacitance (lower than 0.5 pF). Otherwise, it will affect the impedance of the RF loop or
result in attenuation of RF signals. RCLAMP0521P from Semtech or ESD5V3U1U from Infineon is
recommended.
On the PCB, keep the RF signals and RF components away from high-speed circuits, power supplies,
transformers, great inductors, the clock circuit of single-chip host, etc.