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 75 of 129
C1-Public
• ensuring at least 15 – 20 dB isolation between antennas in the GNSS band by implementing the
most suitable placement for the antennas, considering in particular the related radiation diagrams
of the antennas: better isolation results from antenna patterns with radiation lobes in different
directions considering the GNSS frequency band.
• adding a GNSS pass-band SAW filter along the GNSS RF line, providing very large attenuation in
the cellular frequency bands (see Table 26 for possible suitable examples). It has to be noted that,
as shown in Figure 4, a SAW filter and an LNA are already integrated in the GNSS RF path of the
SARA-R422M8S: the addition of an external filter along the GNSS RF line has to be considered
only if the conditions above cannot be met.
Additional countermeasures
In case all the aforementioned countermeasures cannot be implemented, adding a GNSS stop-band
SAW filter along the cellular RF line may be considered. The filter shall provide very low attenuation in
the cellular frequency bands (see Table 33 for possible suitable examples). It has to be noted that the
addition of an external filter along the cellular RF line has to be carefully evaluated, considering that
the additional insertion loss of such filter may affect the cellular TRP and/or TIS RF figures.
Table 33 lists examples of GNSS band-stop SAW filters that may be considered for the cellular RF
input/output in case enough isolation between the cellular and the GNSS RF systems cannot be
provided by proper selection and placement of the antennas beside other proper RF design solutions.
Manufacturer
Part number
Description
Qualcomm
B8636
GPS / SBAS / QZSS / GLONASS / Galileo / BeiDou RF band-stop SAW
filter with low attenuation in Cellular frequency ranges
Qualcomm
B8666
GPS / SBAS / QZSS / GLONASS / Galileo / BeiDou RF band-stop SAW
filter with low attenuation in Cellular frequency ranges
Table 33: Examples of GNSS band-stop SAW filters
Additional considerations
As far as the RF Tx power is involved in the cellular / GNSS RF coexistence, it has to be noted that
high-power transmission occurs very infrequently: typical values are in the range of -3 to 0 dBm (see
Figure 1 in the GSMA official document TS.09 [11]). Therefore, depending on the application, careful
PCB layout, antenna selection and placement should be sufficient to ensure accurate GNSS reception.
For an example of vehicle tracking application in a small form factor featuring cellular and short-range
connectivity alongside a multi-constellation GNSS receiver, with successful RF coexistence between
the systems, refer to the u-blox B36 vehicle tracking blueprint [22]. The distance between the cellular
and GNSS antennas for the u-blox B36 blueprint is annotated in Figure 45.
GNSS
antenna
5.5 cm
Cellular
antenna
SARA
module
Figure 45: PCB top rendering for the u-blox B36 blueprint with annotated distance between cellular and GNSS antennas