Electron 2 vs. SoM decision guide

Basic differences

• ¹ Optional but recommended on base board
• ² Optional on base board, can be omitted if not needed
• ³ External antenna connection via U.FL connector

Connectivity differences

Cellular bands and regions

Cellular bands

There are a large number of cellular bands available, and are generally divided into bands used in the Americas, and bands used in Europe, Middle East, Africa, and Asia (EMEAA). These are popular LTE bands, and there is very little overlap.

To make things more complicated, South America uses a mix of Americas and EMEAA frequencies, depending on the country. There are also many more bands than these; Japan and China use a large number of less common bands.

It's important to note that not every cellular tower will carry every frequency used in a country. Additionally, lower frequencies can travel longer distances so often 700 and 850 MHz are used in rural areas so the towers can be farther apart.

While this table shows LTE frequencies and bands, similar divisions also apply to 2G and 3G.

NorAm

NorAm devices are intended for use in North America: United States, Canada, and Mexico.

In most cases, these are LTE Cat M1 devices, and are only officially supported in these three countries.

Show NorAm SKUs

Americas

The ELC504EM uses LTE Cat 1 with Americas frequencies, which is more widely supported outside of NorAm.

The complication is in South America, where a number of countries use EMEAA frequencies instead of Americas frequencies.

Show Americas SKUs

EMEAA

The ELC524EM uses LTE Cat 1 with EMEAA frequencies, which is compatible in most of Europe, Middle East, Africa, and Africa, as well as some countries in South America.

The ELC524EM only supports LTE Cat 1 and does not support 2G/3G fallback, as the B524 and M524 do. This can be a problem in some countries, particularly in Africa, that have not fully deployed 4G/LTE.

Show EMEAA SKUs

Cellular technologies

LTE Cat 1

LTE Cat 1 is the same technology used for 4G/LTE mobile phone data, and is the most commonly deployed technology in most of the world.

Show LTE Cat 1 SKUs

LTE Cat 1 bis

LTE Cat 1 bis is a simplified version of LTE Cat 1 intended for IoT applications. It uses a single antenna, is intended for low-power devices, and the simplifications make the radio less expensive. It's fully compatible with LTE Cat 1, however, and does not require any tower-side changes, making it available anywhere LTE Cat 1 (4G) is available. It also has the same maximum data rate as LTE Cat 1.

Show LTE Cat 1 bis SKUs

The Particle devices with LTE Cat 1 bis cellular modems do not support 2G/3G fallback. For a comparison of cellular technologies used by country, see Country compatibility, below.

LTE Cat M1

LTE Cat M1 is subset of 4G/LTE intended for low-power and low-cost IoT devices. It's widely deployed in the United States, Canada, and Mexico (NorAm). There is limited coverage in Europe, though it is available in the United Kingdom and Australia on a subset of the available carriers.

If you are deploying a low-power device in the United States, this can be a good choice, however the difference in power consumption between LTE Cat M1 and LTE Cat 1 bis is not very large.

Additional large-scale deployments of LTE Cat M1 in other countries are less likely with the adoption of LTE Cat 1 bis instead.

Show LTE Cat M1 SKUs

2G/3G

The older 2G and 3G technologies are being phased out ("sunset") around the world. The shutdown is already complete in the United States, Australia, and Japan, and will occur soon in Canada.

Additionally, 3G requires more power than 4G/LTE. 2G requires even more than 3G.

The phase-out or sunset of 2G and 3G varies by country in carrier.

In most of Europe, 3G has been or will be phased out first, leaving 2G services.

In many other areas, 2G was or will be phased out first, leaving 3G.

Particle devices with cellular modems with only 2G and 3G have already been deprecated. The LTE Cat 1 devices above can also 2G/3G fallback.

For additional information, see the 2G/3G sunset page.

Other technologies

5G

Only the Tachyon device supports 5G.

For IoT use-cases, 5G generally unnecessary as 4G/LTE data rates are sufficient, and no carriers have a plan to sunset 4G/LTE at this time.

LTE higher Cat

The Tachyon supports up to LTE Cat 14, which is much faster than LTE Cat 1. Not all towers support the highest Cat speeds, but all are backward compatible to LTE Cat 1.

This is different than LTE Cat M1 or LTE Cat NB1 which requires specific support for those technologies by the carrier.

LTE Cat NB1

LTE Cat NB1 is a variation intended for IoT devices, however the data rate is so low that it does not support the ability to do OTA flashing of firmware, and is not supported on any Particle devices.

It's more common in Europe, but still not widely deployed and large-scale deployments are unlikely with the adoption of LTE Cat 1 bis instead.

Form factor

Feather

The Electron 2, Boron, and Photon 2 comply with the Adafruit Feather specification.

All Feather devices have pins on the bottom that plug into a breadboard, baseboard, doubler, or tripler. There are a large number of available base boards off-the-shelf that implement features such as sensors, displays, relays, etc., eliminating the need for a custom-designed board in some cases.

The Feather page includes examples of Feather accessories.

Show Feather SKUs

M.2 SoM

The Particle M.2 SoM allows each swapping between modules and the screw-down module is generally vibration-resistant.

The SoM does not include features like USB, RGB LED, buttons, and a power supply on the module itself; you are expected to include this on the base board, which is required.

The Particle M.2 module is not compatible with computer-based M.2 sockets that are used for NVMe, PCI Express (PCIe), etc. and requires a base board specifically designed for Particle M.2.

While a custom board is generally required, there are some off-the-shelf options such as:

Show M.2 SoM SKUs

MCU differences

Across these devices there are two different MCU used. While software can generally be compiled for each platform, each platform has differences in amount of available RAM and maximum application size.

nRF52840 (Gen 3)

• Best for low-power applications
• Limited RAM and flash size
• ARM Cortex M4F CPU, 64 MHz
• 80 KB RAM available to user applications
• 256 KB maximum application size

Show nRF52840 SKUs

RTL8721DM/RTL8722DM (Gen 4)

• Best for computation, such as machine learning applications such as inferencing
• Larger RAM and flash size
• ARM Cortex M33 CPU, 200 MHz
• 3072 KB RAM available to user applications
• 2048 KB maximum application size

Show RTL872x SKUs

Electron 2 and Photon 2 interoperability

Between the Electron 2 and Photon 2, there are differences in the pins used for PWM, and some differences in other ports. These can sometimes be worked around easily, but sometimes not. For example, it's not possible use SPI1 interchangeably between the Electron 2 and Photon 2 because they're on different pins.

Electron 2 pinout

Photon 2 pinout

GPIO

There are sigificantly more GPIO on M.2 SoM modules than on the Electron 2/Boron (Feather). If you have an application that requires significant GPIO and do not want to use a GPIO expander, the M.2 SoM will be a better choice.

M-SoM pinout

Custom designs

If you have a custom design that requires a specialized power supply, a battery of a different chemistry, etc., then using the M.2 SoM will be preferable since the PMIC and fuel gauge features are not on the SoM and can be swapped for other components on your base board.

GNSS

GNSS (GPS) is a geolocation technology using satellites. It's generally only viable outdoors.

Several Particle devices include built-in GNSS technology in the cellular modem module. Using it requires an external antenna and the antenna must have a clear view of the sky for proper operation.

Even if the cellular module you have selected does not contain GNSS it can easily be added with an external module connected by serial, I2C, or SPI.

Show cellular modem GNSS SKUs

e-sim

The Electron 2 and B504e have a Particle e-sim. Other devices have a Particle MFF2 EtherSIM.

At this time, the carriers installed on the e-sim are the same as the Particle MFF2 (SMD) EtherSIM, and the e-sim is not user programmable.

The e-sim provides a path to future updates to the SIM without having to modify the hardware, however.

Country compatibility

Certification

If you are using the certified Particle antenna you generally will not have to do intentional radiator testing, which is the most complicated and most common certification test.

You will, however, have to do unintentional radiator testing, and it must be repeated for all modules if you swap between different modules based on region or required connectivity. This is the least expensive and easiest certification, however.

Additional information

• Electron 2 datasheet
• Electron 2 from Boron migration guide
• B404X datasheet
• B504 datasheet
• B524/B523 datasheet
• M-SoM datasheet
• Cellular carrier list