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 Supply interfaces
- 1.5.1 Module supply input (VCC)
- 1.5.1.1 VCC supply requirements
- 1.5.1.2 VCC current consumption in LTE connected mode
- 1.5.1.3 VCC current consumption in 2G connected mode
- 1.5.1.4 VCC current consumption in ultra low power deep sleep mode
- 1.5.1.5 VCC current consumption in low power idle mode
- 1.5.1.6 VCC current consumption in active mode (PSM / low power disabled)
- 1.5.2 Generic digital interfaces supply output (V_INT)
- 1.5.1 Module supply input (VCC)
- 1.6 System function interfaces
- 1.7 Antenna interfaces
- 1.8 SIM interface
- 1.9 Data communication interfaces
- 1.10 Audio
- 1.11 General Purpose Input/Output
- 1.12 GNSS peripheral input output
- 1.13 Reserved pins (RSVD)
- 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 LDO linear regulator
- 2.2.1.4 Guidelines for VCC supply circuit design using a rechargeable battery
- 2.2.1.5 Guidelines for VCC supply circuit design using a primary battery
- 2.2.1.6 Guidelines for external battery charging circuit
- 2.2.1.7 Guidelines for external charging and power path management circuit
- 2.2.1.8 Guidelines for particular VCC supply circuit design for SARA-R4x2
- 2.2.1.9 Guidelines for removing VCC supply
- 2.2.1.10 Additional guidelines for VCC supply circuit design
- 2.2.1.11 Guidelines for VCC supply layout design
- 2.2.1.12 Guidelines for grounding layout design
- 2.2.2 Generic digital interfaces supply output (V_INT)
- 2.2.1 Module supply (VCC)
- 2.3 System functions interfaces
- 2.4 Antenna interfaces
- 2.5 SIM interface
- 2.6 Data communication interfaces
- 2.7 Audio
- 2.8 General Purpose Input/Output
- 2.9 GNSS peripheral input output
- 2.10 Reserved pins (RSVD)
- 2.11 Module placement
- 2.12 Module footprint and paste mask
- 2.13 Thermal guidelines
- 2.14 Schematic for SARA-R4 series module integration
- 2.15 Design-in checklist
- 3 Handling and soldering
- 4 Approvals
- 4.1 Product certification approval overview
- 4.2 US Federal Communications Commission notice
- 4.3 Innovation, Science, Economic Development Canada notice
- 4.4 European Conformance CE mark
- 4.5 National Communication Commission Taiwan
- 4.6 ANATEL Brazil
- 4.7 Australian Conformance
- 4.8 GITEKI Japan
- 4.9 KC South Korea
- 5 Product testing
- Appendix
- A Migration between SARA modules
- B Glossary
- Related documentation
- Revision history
- Contact
SARA-R4 series - System integration manual
UBX-16029218 - R20 Design-in Page 72 of 129
C1-Public
To avoid damaging the bias-T series inductor in the case of a short circuit at the antenna connector,
it is recommended to implement a proper over-current protection circuit, which may consist in a series
resistor as in the example illustrated in Figure 42. Component values are calculated according to the
characteristics of the active antenna and the related supply circuit in use: the value of R
bias
is
calculated such that the maximum current capacity of the inductor L is never exceeded. Moreover,
R
bias
and C form a low pass filter to remove high frequency noise from the DC supply. Assuming
VCC_ANT=3.3 V, Table 30 reports suggested components for the circuit in Figure 42.
The recommended bias-t inductor (Murata LQW15ANR12J00) has a maximum current capacity of
110 mA. Hence the current is limited to 100 mA by way of a 33 ohm bias resistor. This resistor power
rating must be chosen to ensure reliability in the chosen circuit design.
SARA-R422M8S
31
ANT_GNSS
GND
LNA
Active antenna
Coaxial antenna
cable
VCC_ANT
Rbias
C
L
44
44
ANT_ON
ESD
Figure 42: Typical circuit with active antenna connected to GNSS RF interface of SARA-R422M8S, using an external supply
Reference
Description
Part number - Manufacturer
L
120 nH wire-wound RF Inductor 0402 5% 110 mA
LQW15ANR12J00 - Murata
C
100 nF capacitor ceramic X7R 0402 10% 16 V
GCM155R71C104KA55 - Murata
Rbias
33 ohm resistor 0.5W
Various manufacturers
Table 30: Example component values for active antenna biasing
☞ Refer to the antenna datasheet and/or manufacturer for proper values of the supply voltage
VCC_ANT, inductance L and capacitance C.
☞ ESD sensitivity rating of the ANT_GNSS RF input pin is 1 kV (HBM according to JESD22-A114).
Higher protection level can be required if the line is externally accessible on the application board.
Higher protection level can be achieved by mounting an ultra low capacitance (i.e. < 1 pF) ESD
protection (see Table 31) close to accessible point.
Table 31 lists examples of ESD protection suitable for the GNSS RF input of SARA-R422M8S.
Manufacturer
Part number
Description
ON Semiconductor
ESD9R3.3ST5G
ESD protection diode with ultra−low capacitance (0.5 pF)
Infineon
ESD5V3U1U-02LS
ESD protection diode with ultra−low capacitance (0.4 pF)
Littelfuse
PESD0402-140
ESD protection diode with ultra−low capacitance (0.25 pF)
Table 31: Examples of ultra−low capacitance ESD protections