UM220-IV L User Manual
UC-00-M15 EN R1.4
Hardware Design
15
4.2
Antenna Design
4.2.1
Passive Antenna
The RF input port of the module can be connected directly to the RF_IN without
providing a DC voltage. There are a few things to note when using a passive antenna:
Select a proper installation position of the antenna to reduce the interference of
electromagnetic noise, so as to enable the optimum performance of the antenna;
A 50 impedance match of RF link is needed;
UM220-IV L
VCC
UC6226
SAW
LNA
FB
VCC_RF
V_ANT
ANT_DET_N
RF_IN
GND
Antenna
Figure 4- 1 UM220-IV L Passive Antenna Solution
To improve the performance of RF analog front-end, a low noise amplifier (LNA) can be
added behind the passive antenna. UM220-IV L module provides a 3.3V power supply
(VCC_RF) for LNA.
Note: If the user has a high requirement for ESD (higher than the maximum specification
in User Manual), the user should consider other method to power the LNA rather than
using the VCC_RF pin. In this case, it is recommended to choose a power supply chip with
high ESD protection level. Gas discharge tube, varistor, TVS tube and other high-power
protective devices may also be used in the power supply circuit to further protect the
module from ESD damage or other Electrical Over-Stress (EOS).
