Integration Guide
Table Of Contents
- Preface
- 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 SIM interface
- 1.9 Serial Communication
- 1.10 Audio
- 1.11 ADC input (LEON-G100 only)
- 1.12 General Purpose Input/Output (GPIO)
- 1.13 M2M Setup Schematic Example
- 1.14 Approvals
- 2 Design-In
- 3 Handling and soldering
- 4 Product Testing
- Appendix
- A Extra Features
- B Glossary
- Related documents
- Revision history
- Contact
LEON-G100/G200 - System Integration Manual
GSM.G1-HW-09002-F3 Preliminary Design-In
Page 85 of 101
2.4.3 Antenna detection functionality
The internal antenna detect circuit is based on ADC measurement at ANT pin: the RF port is DC coupled to the
ADC unit in the baseband chip which injects a DC current (30 µA) on ANT and measures the resulting DC
voltage to evaluate the resistance from ANT pad to GND.
The antenna detection is performed by the measurement of the resistance from ANT pad to GND (DC element
of the GSM antenna), that is forced by the +UANTR AT command: refer to u-blox 2G GSM/GPRS AT Commands
Manual [2] for more details on how to access to this feature.
To achieve good antenna detection functionality, use an RF antenna with built-in resistor from 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 53.
Antenna Assembly
Diagnostic Circuit
Application Board
LEON-G100/G200
ANT
ADC
Current
Source
RF
Choke
DC
Blocking
Front-End
RF Module
RF
Choke
DC
Blocking
Radiating
Element
Zo=50 Ohm
Resistor for
Diagnostic
Coaxial Antenna Cable
Internal
Resistor
Figure 53: Module Antenna Detection circuit and antenna with diagnostic resistor
Examples of components for the antenna detection diagnostic circuit are reported in the following table:
Description
Part Number - Manufacturer
DC Blocking Capacitor
Murata GRM1555C1H220JA01 or equivalent
RF Choke Inductor
Murata LQG15HS68NJ02, LQG15HH68NJ02 or equivalent
Resistor for Diagnostic
15kΩ 5%, various Manufacturers
Table 31: Example of components for the antenna detection diagnostic circuit
Please note that 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 Figure 53, the
measured DC resistance will be always on the extreme of measurement range (respectively open or short), and
there will be no mean to distinguish from defect on antenna path with similar characteristic (respectively:
removal of linear antenna or RF cable shorted to GND for PIFA antenna).