Integration Manual

LISA-U2 series - System Integration Manual
UBX-13001118 - R25 Design-In Page 139 of 182
For example, consider a GSM antenna with built-in DC load resistor of 15 k. Using the +UANTR AT
command, the module reports the resistance value evaluated from the ANT connector to GND:
 Reported values close to the used diagnostic resistor nominal value (i.e. values from 13 kΩ to 17 kΩ
if a 15 kΩ diagnostic resistor is used) indicate that the antenna is properly connected
 Values close to the measurement range maximum limit (approximately 50 kΩ) or an open-circuit
“over range” report (see the u-blox AT Commands Manual [2]) means that that the antenna is not
connected or the RF cable is broken
 Reported values below the measurement range minimum limit (1 kΩ) will highlight a short to GND
at the antenna or along the RF cable
 Measurement inside the valid measurement range and outside the expected range may indicate
an unclean connection, damaged antenna or wrong value of the antenna load resistor for
diagnostic purposes
 Reported value could differ from the real resistance value of the diagnostic resistor mounted
inside the antenna assembly due to the antenna cable length, antenna cable capacity and the used
measurement method
2.5 ESD guidelines
2.5.1 ESD immunity test overview
The immunity of devices integrating LISA-U2 modules to Electrostatic Discharge (ESD) is part of the
Electromagnetic Compatibility (EMC) conformity which is required for products bearing the CE
marking, compliant with the Radio Equipment Directive (2014/53/EU), the EMC Directive (2014/30/EU)
and the Low Voltage Directive (2014/35/EU) issued by the Commission of the European Community.
Compliance with these directives implies conformity with the following European Norms for device
ESD immunity: ESD testing standard CENELEC EN 61000-4-2 [11] and the radio equipment standards
EN 301 489-1 [12], EN 301 489-52 [13], the requirements of which are summarized in Table 51.
The ESD immunity test is performed at the enclosure port, defined by EN 301 489-1 [12] as the physical
boundary through which the electromagnetic field radiates. If the device implements an integral
antenna, the enclosure port is defined as all insulating and conductive surfaces housing the device. If
the device implements a removable antenna, the antenna port can be separated from the enclosure
port. The antenna port includes the antenna element and its interconnecting cable surfaces.
The applicability of the ESD immunity test to the whole device depends on the device classification as
defined by ETSI EN 301 489-1 [12]. Applicability of the ESD immunity test to the specific device ports
or the specific interconnecting cables to auxiliary devices depends on the devices’ accessible
interfaces and manufacturer requirements, as defined by ETSI EN 301 489-1 [12].
Contact discharges are performed at conductive surfaces, while air discharges are performed at
insulating surfaces. Indirect contact discharges are performed on the measurement setup horizontal
and vertical coupling planes as defined in CENELEC EN 61000-4-2 [11].
☞ For the definition of integral antenna, removable antenna, antenna port, device classification see
the ETSI EN 301 489-1 [12].
☞ The contact and air discharges are defined in CENELEC EN 61000-4-2 [11].
Application
Category
Immunity Level
All exposed surfaces of the radio equipment and ancillary
equipment in a representative configuration
Contact Discharge
4 kV
Air Discharge
8 kV
Table 51: ESD immunity requirements as defined by EN 61000-4-2, EN 301 489-1, EN 301 489-52