SX1276MB1xAS

Additional Application Code and Library Examples can be found toward the bottom of this page

SX1276 mbed Component Shield

Overview

The SX1276 transceiver features the LoRa™ long range modem that provides ultra-long range spread spectrum communication and high interference immunity whilst minimising current consumption. Using Semtech’s patented LoRa™ modulation technique the SX1276 can achieve a sensitivity of over -148dBm using a low cost crystal and bill of materials. The high sensitivity combined with the integrated +20 dBm power amplifier yields industry leading link budget making it optimal for any application requiring range or robustness. LoRa™ also provides significant advantages in both blocking and selectivity over conventional modulation techniques, solving the traditional design compromise between range, interference immunity and energy consumption. The device also support high performance (G)FSK modes for systems including WMBus, IEEE802.15.4g. The SX1276 delivers exceptional phase noise, selectivity, receiver linearity and IIP3 for significantly lower current consumption than competing devices. The SX1276 is intended for applications over a wide frequency range and is covering all available sub-GHz frequency bands (168MHz, 434MHz, 470MHz, 868MHz and 902MHz). The SX1276 really offers the possibility of two modems in one single package and complies with both ETSI and FCC regulatory requirements.

LoRa™ Modulation

LoRa™, Semtech’s proprietary modulation is a spread-spectrum technique that uses wideband linear frequency modulated pulses to encode information, whose frequency increases or decreases over a certain amount of time. As with other spread-spectrum modulation techniques, LoRa™ uses the entire channel bandwidth to broadcast a signal, making it robust to channel noise. In addition, because LoRa modulation uses a broad band of the spectrum, it is also resistant to long term relative frequency error, multi-path, fading and Doppler effects.

SX1276 Features

• 168 dB maximum link budget
• +20 dBm - 100 mW constant RF output vs. V supply
• +14 dBm high efficiency PA
• Programmable bit rate up to 300 kbps
• High sensitivity: down to -146.5 dBm
• Bullet-proof front end: IIP3 = -12 dBm
• 100 dB blocking immunity
• Low RX current of 10 mA, 200 nA register retention
• Fully integrated synthesizer with a resolution of 61 Hz
• FSK, GFSK, MSK, GMSK, LORA and OOK modulations
• Built-in bit synchronizer for clock recovery
• Sync word recognition
• Preamble detection
• 115 dB+ Dynamic Range RSSI
• Automatic RF Sense with ultra-fast AFC
• Packet engine up to 64 bytes with CRC
• Built-in temperature sensor and Low Battery indicator

Connectivity

The SX1276MB1MAS and SX1276LB1LAS are controlled through the SPI bus at a maximum speed of 10Mbps. The connections are identical on each board so that the same software can used on any boards. All “Pass through” pins are not used in the operations of the SX1276MB1xAS boards and can therefore be used in connections of other boards for various purposes. The I2C and UART have especially been let free so that a variety of sensor can be connected to the boards, and thus enable long distance control of them.

¹Some platforms have issues with the handling of the interrupt on the pin D8. To solve this issue, the radio pin DIO4 is mapped to both pin D8 and pin A3. The selection of which pin is used can be easily selected in software.

²The status of the RxTx pin is also used at boot up to detect the board connected. Reading a ’1’ means the board connected is a SX1276MB1LAS and reading a ‘0’ indicates a SX1276MB1MAS. For production, the RxTx pin can be directly driven from the RF chipset by removing R16 and fitting R15.

SX1276MB1LAS

The SX1276MB1LAS is especially designed around two ISM frequency band available in North America: 433 MHz and 915 MHz. The SX1276MB1LAS uses a dedicated output pin so it can achieve 20dBm on the HF output and the maximum power is limited to 14 dBm on the LF output.
SX1276MB1LAS Schematic
SX1276MB1LAS Layout
SX1276MB1LAS BOM

SX1276MB1MAS

The SX1276MB1LAS is especially designed around two ISM frequency band available in Europe and China: 433 MHz and 868 MHz. The SX1276MB1MAS uses the high efficiency output on both frequency bands thus limiting the output power to 14dBm.
SX1276MB1MAS Schematic
SX1276MB1MAS Layout
SX1276MB1MAS BOM

Documentation and Software

SX1276 Datasheet
LoRa Modem Designer's Guide
LoRa Low Energy Design Guide
LoRa Calculator: fast evaluation of link budget, time on air and energy consumption

Additional Application Examples

1.) LoRaWAN

LoRaWAN Class A and Class C node example based on GitHub LoRaMac-node LoRaWAN MAC layer implementation

2.) SX1276 Ping Pong FHSS Demo Application

3.) SX1276 Tx Continuous Wave Demo Application

Where to buy

SX1276MB1MAS:

SX1276MB1LAS: