User's Manual
Table Of Contents
- Preface
- Contents
- 1 System description
- 1.1 Overview
- 1.2 Architecture
- 1.3 Pin-out
- 1.4 Operating modes
- 1.5 Supply interfaces
- 1.6 System function interfaces
- 1.7 Antenna interface
- 1.8 SIM interface
- 1.9 Serial interfaces
- 1.9.1 Asynchronous serial interface (UART)
- 1.9.1.1 UART features
- 1.9.1.2 UART AT interface configuration
- 1.9.1.3 UART signal behavior
- 1.9.1.4 UART and power-saving
- AT+UPSV=0: power saving disabled, fixed active-mode
- AT+UPSV=1: power saving enabled, cyclic idle/active-mode
- AT+UPSV=2: power saving enabled and controlled by the RTS line
- AT+UPSV=3: power saving enabled and controlled by the DTR line
- Wake up via data reception
- Additional considerations for SARA-U2 modules
- 1.9.1.5 Multiplexer protocol (3GPP 27.010)
- 1.9.2 Auxiliary asynchronous serial interface (UART AUX)
- 1.9.3 USB interface
- 1.9.4 DDC (I2C) interface
- 1.9.1 Asynchronous serial interface (UART)
- 1.10 Audio interface
- 1.11 General Purpose Input/Output (GPIO)
- 1.12 Reserved pins (RSVD)
- 1.13 System features
- 1.13.1 Network indication
- 1.13.2 Antenna detection
- 1.13.3 Jamming detection
- 1.13.4 TCP/IP and UDP/IP
- 1.13.5 FTP
- 1.13.6 HTTP
- 1.13.7 SMTP
- 1.13.8 SSL
- 1.13.9 Dual stack IPv4/IPv6
- 1.13.10 Smart temperature management
- 1.13.11 AssistNow clients and GNSS integration
- 1.13.12 Hybrid positioning and CellLocateTM
- 1.13.13 Firmware upgrade Over AT (FOAT)
- 1.13.14 Firmware upgrade Over The Air (FOTA)
- 1.13.15 In-Band modem (eCall / ERA-GLONASS)
- 1.13.16 SIM Access Profile (SAP)
- 1.13.17 Power saving
- 2 Design-in
- 2.1 Overview
- 2.2 Supply interfaces
- 2.2.1 Module supply (VCC)
- 2.2.1.1 General guidelines for VCC supply circuit selection and design
- 2.2.1.2 Guidelines for VCC supply circuit design using a switching regulator
- 2.2.1.3 Guidelines for VCC supply circuit design using a Low Drop-Out (LDO) linear regulator
- 2.2.1.4 Guidelines for VCC supply circuit design using a rechargeable Li-Ion or Li-Pol battery
- 2.2.1.5 Guidelines for VCC supply circuit design using a primary (disposable) battery
- 2.2.1.6 Additional guidelines for VCC supply circuit design
- 2.2.1.7 Guidelines for external battery charging circuit
- 2.2.1.8 Guidelines for external battery charging and power path management circuit
- 2.2.1.9 Guidelines for VCC supply layout design
- 2.2.1.10 Guidelines for grounding layout design
- 2.2.2 RTC supply (V_BCKP)
- 2.2.3 Interface supply (V_INT)
- 2.2.1 Module supply (VCC)
- 2.3 System functions interfaces
- 2.4 Antenna interface
- 2.5 SIM interface
- 2.6 Serial interfaces
- 2.6.1 Asynchronous serial interface (UART)
- 2.6.1.1 Guidelines for UART circuit design
- 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
- 2.6.1.2 Guidelines for UART layout design
- 2.6.1.1 Guidelines for UART circuit design
- 2.6.2 Auxiliary asynchronous serial interface (UART AUX)
- 2.6.3 Universal Serial Bus (USB)
- 2.6.4 DDC (I2C) interface
- 2.6.1 Asynchronous serial interface (UART)
- 2.7 Audio interface
- 2.7.1 Analog audio interface
- 2.7.1.1 Guidelines for microphone and speaker connection circuit design (headset / handset modes)
- 2.7.1.2 Guidelines for microphone and loudspeaker connection circuit design (hands-free mode)
- 2.7.1.3 Guidelines for external analog audio device connection circuit design
- 2.7.1.4 Guidelines for analog audio layout design
- 2.7.2 Digital audio interface
- 2.7.1 Analog audio interface
- 2.8 General Purpose Input/Output (GPIO)
- 2.9 Reserved pins (RSVD)
- 2.10 Module placement
- 2.11 Module footprint and paste mask
- 2.12 Thermal guidelines
- 2.13 ESD guidelines
- 2.14 SARA-G350 ATEX integration in explosive atmospheres applications
- 2.15 Schematic for SARA-G3 and SARA-U2 series module integration
- 2.16 Design-in checklist
- 3 Handling and soldering
- 4 Approvals
- 5 Product testing
- Appendix
- A Migration between LISA and SARA-G3 modules
- A.1 Overview
- A.2 Checklist for migration
- A.3 Software migration
- A.4 Hardware migration
- B Migration between SARA-G3 and SARA-U2
- C Glossary
- Related documents
- Revision history
- Contact
SARA-G3 and SARA-U2 series - System Integration Manual
UBX-13000995 - R08 Objective Specification Design-in
Page 88 of 188
C4
GND
C3 C2
SARA-G3 / SARA-U2
52
VCC
53
VCC
51
VCC
3V8
C1
+
C5
Figure 39: Suggested schematic and layout design for the VCC bypass capacitors to reduce ripple / noise on VCC voltage profile
and to avoid undershoot / overshoot on VCC voltage drops
Reference
Description
Part Number - Manufacturer
C1
330 µF Capacitor Tantalum D_SIZE 6.3 V 45 m
T520D337M006ATE045 - KEMET
C2
100 nF Capacitor Ceramic X7R 0402 10% 16 V
GRM155R71C104KA01 - Murata
C3
10 nF Capacitor Ceramic X7R 0402 10% 16 V
GRM155R71C103KA01 - Murata
C4
56 pF Capacitor Ceramic C0G 0402 5% 25 V
GRM1555C1E560JA01 - Murata
C5
15 pF Capacitor Ceramic C0G 0402 5% 25 V
GRM1555C1E150JA01 - Murata
Table 19: Suggested components to reduce ripple / noise on VCC and to avoid undershoot/ overshoot on VCC voltage drops
ESD sensitivity rating of the VCC supply pins is 1 kV (Human Body Model according to JESD22-A114).
Higher protection level can be required if the line is externally accessible on the application board, e.g. if
accessible battery connector is directly connected to VCC pins. Higher protection level can be achieved by
mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor array) close to accessible point.
2.2.1.7 Guidelines for external battery charging circuit
Application devices that are powered by a Li-Ion (or Li-Polymer) battery pack should implement a suitable battery
charger design as SARA-G3 and SARA-U2 series modules do not have an on-board charging circuit.
In the application circuit example described in Figure 40, a rechargeable Li-Ion (or Li-Polymer) battery pack, that
features proper pulse and DC discharge current capabilities and proper DC series resistance, is directly connected
to the VCC supply input of the module. Battery charging is fully managed by the STMicroelectronics L6924U
Battery Charger IC that, from a USB source (5.0 V typ.), charges as a linear charger the battery, in three phases:
Pre-charge constant current (active when the battery is deeply discharged): the battery is charged with a
low current, set to 10% of the fast-charge current
Fast-charge constant current: the battery is charged with the maximum current, configured by the value
of an external resistor to a value suitable for USB power source (~500 mA)
Constant voltage: when the battery voltage reaches the regulated output voltage (4.2 V), the L6924U
starts to reduce the current until the charge termination is done. The charging process ends when the
charging current reaches the value configured by an external resistor to ~15 mA or when the charging timer
reaches the value configured by an external capacitor to ~9800 s
Using a battery pack with an internal NTC resistor, the L6924U can monitor the battery temperature to protect
the battery from operating under unsafe thermal conditions.
The L6924U, as linear charger, is more suitable for applications where the charging source has a relatively low
nominal voltage (~5 V), so that a switching charger is suggested for applications where the charging source has
a relatively high nominal voltage (e.g. ~12 V, refer to the following section 2.2.1.8 for specific design-in), even if