u-blox LEA-6 Series - Page 35

LEA-6 / NEO-6 - Hardware Integration Manual
GPS.G6-HW-09007-A Preliminary Design-in
Page 35 of 62
Short Circuit Detection (SCD)
A short circuit in the active antenna pulls V_ANT to ground. This is detected inside the u-blox 6 module and the
antenna supply voltage will be immediately shut down.
Antenna short detection (SCD) and control is enabled by default.
Open Circuit Detection (OCD)
R1
R2
R3
−
+
u-blox 6 Module
GND
RF_IN
GND
V_ANT
VCC_RF
AADET_N
u1
Figure 30: Schematic of open circuit detection variant A (for exact pin orientation see data sheet)
References Value Tolerance Description Remarks
R1
10 Ω ± 5%
Resistor, min 0.063 W
R2
560 Ω ± 5%
Resistor
R3
100 kΩ ± 5%
Resistor
u1 LT6000 Rail to Rail Op Amp
Table 7: Active antenna supervisor, bill of material
RFVcc
R
RR
R
I _
1
32
2
•






+
=
Equation 1: Calculation of threshold current for open circuit detection
If the antenna supply voltage is not derived from Vcc_RF, do not exceed the maximum voltage rating of
AADET_N.
The open circuit detection circuit uses the current flow to detect an open circuit in the antenna. The threshold
current can be calculated using Equation 1.
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