UC-00-M15 EN R1.4
Hardware Design
20
2)
Antenna Short-circuit and Open-circuit Detection
If the short-circuit and open-circuit detection functions of the module are required
concurrently, use the ANT_DET_N pin to cooperate with an external circuit. The
threshold current for open circuit detection can be calculated by formula (4-1). When
the antenna working current is less than the calculated value, the module determines
that the antenna is open-circuit. The resistance of the series resistor R1 can be adjusted
according to the antenna working current.
Coaxial Aerial Cable
R1 10
Ω
R2
560
Ω
R3
100K
Ω
-
+
OP
LT6000
100nF
UM220-IV L
VCC
UC6226
SAW
LNA
FB
VCC_RF
V_ANT
ANT_DET_N
RF_IN
GND
Active Antenna
Figure 4- 7 UM220-IV L Antenna Short-circuit and Open-circuit Detection Powered by VCC_RF
I
=
(
𝑅2
𝑅2+𝑅3
)
𝑅1
𝑉
𝑐𝑐
_𝑅𝐹
（
4-1
）
If an external power supply is used to power the antenna, the maximum power supply
voltage cannot exceed 5.5V to protect the ANT_DET_N pin.
Use ANTSTAT to query the antenna state.
