S100 Slave - LoRa RFM9X


The LoRa RFM9X is a certified Rhomb.io module that allows wide range wireless communications based in the LoRa Alliance specification. This module offers a complete long range, low power consumption and secure data transmission. The LoRa RFM9X module allows communications far more than 15km in rural areas and more than 2 km in urban areas, so it is conceived to bring to your Rhomb.io platform based product the connectivity needed for the Internet of Things (IoT).

There are variants of the LoRa RFM9X module that are compliant with regulations for use in the United States, Canada, Australia New Zealand and Europe. It is the responsibility of the buyer to accomplish with the regulations of the country or countries in wich the module will be used. The following table indicates the differences in between the variants.

LoRa RFM9X module variants
Part Number Frequency (MHz)
RFM95W 868
RFM96W 433
RFM98W 470

The next figure show a 3D view for the LoRa RFM9X module.

LoRa RFM9X module 3D Top v2.png LoRa RFM9X module 3D Bottom v2.png


  • IoT
  • Wearables
  • Smart cities
  • Farming
  • Industrial monitoring and control
  • Education

Module specifications

LoRa™ is a Long Range-Low Rate specification designed for wireless battery-operated and secure data transmission. LoRa™ has been conceived for the Internet of Things (IoT) and uses unlicensed radio spectrum in the Industrial, Scientific and Medical (ISM) bands to enable low power communication in between remote devices.

The LoRa RFM9X module is based on the HopeRF RFM9xW LoRa™ SiP (System in Package) family. Those transceivers feature the LoRa™ long range modem that provides ultra-long range spread spectrum communication and high interference immunity whilst minimizing current consumption. The module can achieve a sensitivity of over -148 dBm and has an internal +20 dBm power amplifier that make it perfect for applications requiring range and robustness. The following table summarizes the main features of the LoRa RFM9X module.

LoRa TM (RFM9x) Key Features
LoRa TM long range transceiver module for wide frequency range
LoRa Modem; 433/470/868/915 MHz license-free ISM bands; 168 dB maximun link budget +20 dBm - 100 mW constant RF output vs. V supply
Programmable bit rate up to 300 kbps
High Sensitivity: down to -148 dBm
Low current: RX = 10.3 mA, 200 nA register retention
127 dB Dynamic Range RSSI; SPI interface
Op. Voltage: 1.8 V to 3.3 V
Op. Temperature: -25 ºC to +85 ºC

As it can be seen on the Block Diagram, the LoRa RFM9X module uses a few lines of the Rhomb.io standard module socket. This is a slave module that should be managed through the SPI bus and that is fed by the 3.3 V Buck 9 signal. There is a UMMC male connector for the antenna but there also a trough-hole pad for wire antennas. Is not recommended to work without an antenna, otherwise, the module could be damaged due to RF reflections.

LoRa RFM9X module Block Diagram v3.jpg

There are also 7 GPIO signals connected to the RFM9xW SiP. The GPIO5 signal is used in order to reset the device. The other 6 GPIOs are software programmable digital input/outputs. It is recommended to read the manufacturer documentation to see the functionality of those GPIOs.



The following table summarizes the GPIOs used on the LoRa RFM9X Module.

Rhomb.io pinout Signal (module) Device Interruption

Note that the GPIO5 is the RFM9xW SiP (System in Package) RESET signal. The other GPIO are connected to a software programmable digital inputs/outputs. It is recommended to read the manufacturer documentation to see the functionality of those GPIOs. The Rhomb.io standard specifications give also more details regarding the Rhomb.io GPIOs.

Serial interfaces

The following table indicates the available serial interfaces on the Rhomb.io standard and it is been indicated the used ones. The table also shows the nomenclature used on the Rhomb.io standard and its corresponding on the schematic.

Signal (Rhomb.io) Signal (module) Used by Signal (Rhomb.io) Signal (module) Used by

As it has been explained in the "Module specifications" section, the LoRa RFM9X module is controlled trough SPI. For more details, look at the module specifications for the Rhomb.io standard and at the manufacturer documentation.


The Secure Digital Input Output (SDIO) interfaces are not used on the LoRa RFM9X Module.


As per the supply lines used on the board, there is a summary on the next table.

Signal (Rhomb.io) Signal (module) Voltage (V) Used
1V8 150mA 1.8 No
2V8 150mA 2.8
VSYS 3 - 5.5
Buck8 3.3
Buck9 3V3 3.3 Yes

As it can be seen on the table, the module is fed by the Buck9 at 3.3 V. For more details, look at the module specifications for the Rhomb.io standard.

Other signals

The CLK_32KH, AD_OUT and PWM_INT signals are not used on the LoRa RFM9X Module. More information regarding these signals can be found at the specifications for the Rhomb.io standard.


Click the image below to download the schematic files.

Bill of materials

Click the image below to download the BOM files.

Fabrication files

Click the image below to download the fabrication files.


  • Precaution against Electrostatic Discharge. When handling Rhomb.io products, ensure that the environment is protected against static electricity. Follow the next recommendations:
  1. The users should wear anti-static clothing and use earth band when manipulating the device.
  2. All objects that come in direct contact with devices should be made of materials that do not produce static electricity that would cause damage.
  3. Equipment and work table must be earthed.
  4. Ionizer is recommended to remove electron charge.
  • Contamination. Be sure to use semiconductor products in the environment that may not be exposed to dust or dirt adhesion.
  • Temperature/Humidity. Semiconductor devices are sensitive to environment temperature and humidity. High temperature or humidity may deteriorate semiconductor devices characteristics. Therefore avoid storage or usage in such conditions.
  • Mechanical Shock. Care should be exercised not to apply excessive mechanical shock or force on the connectors and semiconductors devices.
  • Chemical. Do not expose semiconductor device to chemical because reaction to chemical may cause deterioration of device characteristics.
  • Light Protection. In case of non-EMC (Epoxy Molding Compound) package, do not expose semiconductor IC to strong light. It may cause devices malfunction. Some special products which utilize the light or have security function are excepted from this specification.
  • Radioactive, Cosmic and X-ray. Semiconductor devices can be influenced by radioactive, cosmic ray or X-ray. Radioactive, cosmic and X-ray may cause soft error during device operation. Therefore semiconductor devices must be shielded under environment that may be exposed to radioactive, cosmic ray or X-ray.
  • EMS (Electromagnetic Susceptibility). Note that semiconductor devices characteristics may be affected by strong electromagnetic waves or magnetic field during operation.


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