Integration Manual
Table Of Contents
- Document Information
- Contents
- 1 System description
- 1.1 Overview
- 1.2 Architecture
- 1.3 Pin-out
- 1.4 Operating modes
- 1.5 Power management
- 1.6 System functions
- 1.7 RF connection
- 1.8 (U)SIM interface
- 1.9 Serial communication
- 1.9.1 Serial interfaces configuration
- 1.9.2 Asynchronous serial interface (UART)
- 1.9.2.1 UART features
- 1.9.2.2 UART signal behavior
- 1.9.2.3 UART and power-saving
- 1.9.2.4 UART application circuits
- Providing the full RS-232 functionality (using the complete V.24 link)
- Providing the TxD, RxD, RTS, CTS and DTR lines only (not using the complete V.24 link)
- Providing the TxD, RxD, RTS and CTS lines only (not using the complete V.24 link)
- Providing the TxD and RxD lines only (not using the complete V24 link)
- Additional considerations
- 1.9.3 USB interface
- 1.9.4 SPI interface
- 1.9.5 MUX protocol (3GPP TS 27.010)
- 1.10 DDC (I2C) interface
- 1.11 Audio Interface
- 1.12 General Purpose Input/Output (GPIO)
- 1.13 Reserved pins (RSVD)
- 1.14 Schematic for LISA-U2 module integration
- 1.15 Approvals
- 1.15.1 European Conformance CE mark
- 1.15.2 US Federal Communications Commission notice
- 1.15.3 Innovation, Science, Economic Development Canada notice
- 1.15.4 Australian Regulatory Compliance Mark
- 1.15.5 ICASA Certification
- 1.15.6 KCC Certification
- 1.15.7 ANATEL Certification
- 1.15.8 CCC Certification
- 1.15.9 Giteki Certification
- 2 Design-In
- 3 Features description
- 3.1 Network indication
- 3.2 Antenna detection
- 3.3 Jamming Detection
- 3.4 TCP/IP and UDP/IP
- 3.5 FTP
- 3.6 HTTP
- 3.7 SSL/TLS
- 3.8 Dual stack IPv4/IPv6
- 3.9 AssistNow clients and GNSS integration
- 3.10 Hybrid positioning and CellLocate®
- 3.11 Control Plane Aiding / Location Services (LCS)
- 3.12 Firmware update Over AT (FOAT)
- 3.13 Firmware update Over the Air (FOTA)
- 3.14 In-Band modem (eCall / ERA-GLONASS)
- 3.15 SIM Access Profile (SAP)
- 3.16 Smart Temperature Management
- 3.17 Bearer Independent Protocol
- 3.18 Multi-Level Precedence and Pre-emption Service
- 3.19 Network Friendly Mode
- 3.20 Power saving
- 4 Handling and soldering
- 5 Product Testing
- Appendix
- A Migration from LISA-U1 to LISA-U2 series
- A.1 Checklist for migration
- A.2 Software migration
- A.2.1 Software migration from LISA-U1 series to LISA-U2 series modules
- A.3 Hardware migration
- A.3.1 Hardware migration from LISA-U1 series to LISA-U2 series modules
- A.3.2 Pin-out comparison LISA-U1 series vs. LISA-U2 series
- A.3.3 Layout comparison LISA-U1 series vs. LISA-U2 series
- B Glossary
- Related documents
- Revision history
- Contact
LISA-U2 series - System Integration Manual
UBX-13001118 - R25 Design-In Page 138 of 182
2.4.4 Antenna detection functionality
The internal antenna detect circuit is based on ADC measurement at ANT: the RF port is DC coupled
to the ADC unit in the baseband chip which injects a DC current (10 µ A for 128 µ s) on ANT and
measures the resulting DC voltage to evaluate the resistance from the ANT pad to GND.
The antenna detection is forced by the +UANTR AT command: see the u-blox AT Commands
Manual [2] for more details on how to access this feature.
To achieve antenna detection functionality, use an RF antenna with a built-in resistor from the ANT
signal to GND, or implement an equivalent solution with a circuit between the antenna cable
connection and the radiating element as shown in Figure 67.
Application Board Antenna Assembly
Diagnostic Circuit
LISA-U2 series
ADC
Current
Source
RF
Choke
DC
Blocking
Front-End
RF Module
RF
Choke
DC
Blocking
Radiating
Element
Zo=50 Ω
Resistor for
Diagnostic
Coaxial Antenna Cable
ANT
Figure 67: Antenna detection circuit and antenna with diagnostic resistor
Examples of components for the antenna detection diagnostic circuit are listed in the following table:
Description
Part Number - Manufacturer
DC Blocking Capacitor
Murata GRM1555C1H220JA01 or equivalent
RF Choke Inductor
Murata LQG15HS68NJ02, LQG15HH68NJ02 or equivalent (Self Resonance Frequency ~1GHz)
Resistor for Diagnostic
15 k 5%, various Manufacturers
Table 50: Example of components for the antenna detection diagnostic circuit
The DC impedance at RF port for some antennas may be a DC open (e.g. linear monopole) or a DC short
to reference GND (e.g. PIFA antenna). For those antennas, without the diagnostic circuit of Figure 67,
the measured DC resistance will always be at the limits of the measurement range (respectively open
or short), and there will be no means to distinguish between a defect on the antenna path with similar
characteristics (respectively: removal of a linear antenna or RF cable shorted to GND for a PIFA
antenna).
Furthermore, any other DC signal injected to the RF connection from the ANT connector to the
radiating element will alter the measurement and produce invalid results for antenna detection.
☞ It is recommended to use an antenna with a built-in diagnostic resistor in the range from 5 kΩ to
30 kΩ to assure good antenna detection functionality and to avoid a reduction of module RF
performance. The choke inductor should exhibit a parallel Self Resonance Frequency (SRF) in the
range of 1 GHz to improve the RF isolation of the load resistor.