Installation Instructions

LISA-U2 series - System Integration Manual
UBX-13001118 - R19 Early Production Information System description
Page 44 of 175
1.7 RF connection
The ANT pin, provided by all LISA-U2 modules, represents the main RF input/output used to transmit and receive
the 2G and 3G RF signal: the main antenna must be connected to this pad. The ANT pin has a nominal
characteristic impedance of 50  and must be connected to the antenna through a 50  transmission line to
allow transmission and reception of radio frequency (RF) signals in the 2G and 3G operating bands.
The ANT_DIV pin, provided by LISA-U230 modules, represents the RF input for the integrated diversity receiver
implemented for both 2G and 3G cases: the antenna for the Rx diversity must be connected to this pad. The
ANT_DIV pin has a nominal characteristic impedance of 50  and must be connected to the antenna for the Rx
diversity through a 50  transmission line to allow reception of radio frequency (RF) signals, improving the
cellular link quality and reliability on all 2G and 3G operating bands except the 2G DCS 1800.
Name
Module
Description
Remarks
ANT
All
RF input/output for main Tx/Rx antenna
Zo = 50  nominal characteristic impedance.
ANT_DIV
LISA-U230
RF input for Rx diversity antenna
Zo = 50  nominal characteristic impedance.
Table 20: Antenna pins
ESD immunity rating of ANT port is 1000 V (according to IEC 61000-4-2). Higher protection level could be
required if the line is externally accessible on the application board (for further details see section 2.5.3).
Choose an antenna with optimal radiating characteristics for the best electrical performance and overall module
functionality. An internal antenna, integrated on the application board, or an external antenna, connected to the
application board through a proper 50  connector, can be used. See section 2.4 and section 2.2.1.1 for further
details regarding antenna guidelines.
The recommendations of the antenna producer for correct installation and deployment (PCB
layout and matching circuitry) must be followed.
If an external antenna is used, the PCB-to-RF-cable transition must be implemented using either a suitable 50 
connector, or an RF-signal solder pad (including GND) that is optimized for 50  characteristic impedance.
If antenna supervisor functionality is required, the main antenna connected to the ANT pin should have a built in
DC diagnostic resistor to ground to get proper detection functionality (See section 2.4.4).
Connect the Rx diversity antenna to the ANT_DIV pin of LISA-U230 modules unless the 2G and 3G Rx
diversity feature is disabled by AT command (see the u-blox AT Commands Manual [2], +URXDIV
command). The same pin (74) is marked RSVD (reserved) on the other modules that do not implement Rx
diversity: in this case the RSVD pin can be left unconnected.