N27 Hardware User Guide
Chapter 4 Application Interfaces
Copyright © Neoway Technology Co., Ltd. All rights reserved.
38
Figure 4-19 Pi network
ANT
N27
module
Z1
Z2
D1
Z3
Schematic guidelines:
Element components in the above figures are capacitors, inductors, and 0Ω resistors. Place
these RLC components as close to the antenna interface as possible.
Add an ESD protector if the antenna might generate static electricity. The protector can be a TVS
diode with a junction capacitance of lower than 0.5 pF. Ensure that the reverse breakdown
voltage of the TVS is greater than 10V (above 15 V is recommended).
PCB layout guidelines:
Lay copper foil around the RF connector. Dig as many ground holes as possible on the copper to
ensure the lowest grounding impedance.
Keep the trace between N27 and the antenna connector as short as possible. Control the trace
impedance to 50Ω.
If customers adopt an SMA connector, a big RF solder pad might result in great parasitic
capacitance, which will affect the antenna performance. Remove the copper on the first and
second layers under the RF solder pad.
Figure 4-20 Recommended RF PCB design
