User's Manual

N
720 Hardware User Guide
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as possible. The power supply of the active antenna is fed by the 100 nH inductance through the
signal traces.
Common active antenna requires 3.3V to 5V power supply. Though the active antenna has a low
power consumption, it requires stable and clean power supply. You are advised to use
high-performance LDO to supply power for the antenna through a 100 nH inductance, as shown
inFigure 3-6.
Figure 3-6 Power supply reference for active antenna
It is recommended that you add an ESD protection diode to the antenna interface in an
environment with great electromagnetic interference and other applications with badly 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.