The SARA-R540S from u-blox is an LTE-M/NB-IoT module that is designed specifically for 400-450 MHz spectrum bands (bands 31, 72, 73, 87 and 88) available in Europe, Asia, and Latin America. These lower-frequency bands have good propagation characteristics, helping customers in the smart meter, public safety, smart grid, and smart cities markets meet strict indoor and outdoor coverage requirements that might otherwise be difficult to reach over standard cellular connectivity options.
The module delivers an uplink data rate of 1200 kbit/s (Cat M1 half-duplex), 140 kbits/s (Cat NB2 half-duplex) and a downlink data rate of 375 kbits/s (Cat M1 half-duplex), 125 kbit/s (Cat NB2 half-duplex). It supports Power Class 3 transmission over standard LTE bands and Power Class 2, at an enhanced 26 dBm maximum output power, in the 450 MHz spectrum. The module requires a DC supply of 3.8 V and draws less than 1 μA of current in power-saving mode. The module features a 'last-gasp' function to send a last message before it finally loses its power supply, for example, during a power outage or in case of a tampering event.
The SARA-R540S is based on u-blox’s UBX-R5 cellular chipset and supports software features like PSM and eDRX power saving modes, antenna dynamic tuning, CellTime for robust and accurate timing reference, jamming detection, antenna and SIM detection and CellLocate for positioning. It is a Secure Cloud module supporting u-blox IoT-Security-as-a-Service and includes an internal, hardware-based, secure element and a lightweight pre-shared key management system that guarantees security and provides security-based features and services like local data protection, zero touch provisioning, anti-cloning, and secure chip-to-chip communication.
The module is available in an LGA package that measures 16.0 x 26.0 x 2.2 mm and can be controlled via UART, DDC (I2C), USB, GPIO and (U)SIM interfaces. It is ideal for smart metering, smart grid, smart city, IoT and public safety applications.