LEA-6 / NEO-6 / MAX-6 - Hardware Integration Manual
UBX-14054794
Production Information
Design-in
Page 45 of 85
References
Value
Tolerance
Description
Manufacturer
R_BIAS
10
10%
Resistor, min 0.250 W
Table 17: Short circuit protection, bill of material
Short circuits on the antenna input without limitation (R_BIAS) of the current can result in
permanent damage to the receiver! Therefore, it’s recommended to implement an R_BIAS in all
risk applications, such as situations where the antenna can be disconnected by the end-user or
that have long antenna cables.
An additional R_BIAS is not required when using a short and open active antenna supervisor circuitry as
defined in
Section 2.6.4.1
, as the R_BIAS is equal to R2.
2.6.4
Active antenna supervisor (LEA-6)
u-blox 6 Technology provides the means to implement an active antenna supervisor with a minimal number of
parts. The antenna supervisor is highly configurable to suit various different applications.
u-blox 6 Module
GND
RF_IN
GND
Active Antenna
V_ANT
VCC_RF
LNA
AADET_N
Antenna
Supervisor
Circuitry
external
antenna
voltage
supply
Figure 44: External antenna power supply with full antenna supervisor (for exact pin orientation see data sheet)
2.6.4.1
Short and open circuit active antenna supervisor
The Antenna Supervisor can be configured by a serial port message (using only UBX binary message). When
enabled the active antenna supervisor produces serial port messages (status reporting in NMEA and/or UBX
binary protocol) which indicates all changes of the antenna circuitry (
disabled
antenna supervisor, antenna
circuitry
ok
,
short
circuit,
open
circuit) and shuts the antenna supply down if required. Active antenna status
can be determined also polling UBX-MON-HW.
The active antenna supervisor provides the means to check the active antenna for open and short circuits and to
shut the antenna supply off, if a short circuit is detected. The state diagram in Figure 45 applies. If an antenna is
connected, the initial state after power-up is “Active Antenna OK”.
