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 consumption in deep-sleep mode (low power mode and PSM enabled)
- 1.5.1.4 VCC current consumption in low power idle mode (low power mode enabled)
- 1.5.1.5 VCC current consumption in active mode (low power mode and PSM 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 (GPIO)
- 1.12 Reserved pin (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 low drop-out 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 removing VCC supply
- 2.2.1.9 Additional guidelines for VCC supply circuit design
- 2.2.1.10 Guidelines for VCC supply layout design
- 2.2.1.11 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
- 2.6.1 UART interfaces
- 2.6.1.1 Guidelines for UART circuit design
- Providing 1 UART with the full RS-232 functionality (using the complete V.24 link)
- Providing 1 UART with the TXD, RXD, RTS, CTS, DTR and RI lines only
- Providing 1 UART with the TXD, RXD, RTS and CTS lines only
- Providing 2 UARTs with the TXD, RXD, RTS and CTS lines only
- Providing 1 UART with the TXD and RXD lines only
- Providing 2 UARTs with the TXD and RXD lines only
- Additional considerations
- 2.6.1.2 Guidelines for UART layout design
- 2.6.1.1 Guidelines for UART circuit design
- 2.6.2 USB interface
- 2.6.3 SPI interfaces
- 2.6.4 SDIO interface
- 2.6.5 DDC (I2C) interface
- 2.6.1 UART interfaces
- 2.7 Audio
- 2.8 General purpose input / output (GPIO)
- 2.9 Reserved pin (RSVD)
- 2.10 Module placement
- 2.11 Module footprint and paste mask
- 2.12 Schematic for SARA-R5 series module integration
- 2.13 Design-in checklist
- 3 Handling and soldering
- 4 Approvals
- 5 Product testing
- Appendix
- A Migration between SARA modules
- B Glossary
- Related documents
- Revision history
- Contact
SARA-R5 series - System integration manual
UBX-19041356 - R03 System description Page 29 of 123
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1.7.3 Cellular antenna detection interface (ANT_DET)
The antenna detection is based on ADC measurement. The ANT_DET pin is an analog to digital
converter (ADC) provided to sense the antenna presence.
The antenna detection function provided by ANT_DET pin is an optional feature that can be
implemented if the application requires it. The antenna detection is forced by the +UANTR AT
command. See the SARA-R5 series AT commands manual [2] for more details on this feature.
The ANT_DET pin generates a DC current (for detailed characteristics see the SARA-R5 series data
sheet [1]) and measures the resulting DC voltage, thus determining the resistance from the antenna
connector provided on the application board to GND. So, the requirements to achieve antenna
detection functionality are the following:
an RF antenna assembly with a built-in resistor (diagnostic circuit) must be used
an antenna detection circuit must be implemented on the application board
See section 2.4.4 for antenna detection circuit on application board and diagnostic circuit on antenna
assembly design-in guidelines.
1.7.4 Cellular and GNSS coexistence
Desensitization or receiver blocking is a form of electromagnetic interference where a radio receiver
is unable to detect a weak signal that it might otherwise be able to receive when there is no
interference (see Figure 17). Good blocking performance is particularly important in the scenarios
where a number of radios of various forms are used in close proximity to each other. This is the case
with SARA-R510M8S modules integrating both an LTE radio and a GNSS receiver.
0
-120
-60
1575
Frequency [MHz]
Power [dBm]
Filter gain [dB]
1800
2025
1350
1125
GNSS signal
LTE signal
Filter response
Figure 17: Interference signals due to LTE transmission. Low channels in LTE B3, B4 and B66 (1710 MHz) are close to GNSS
frequencies (1561 to 1605 MHz). Harmonics due to transmission in LTE B13 and B18 may also fall into the GNSS bands.