The World’s Smallest LTE Cat M1 Module: u-blox’s SARA-R404M

April 24, 2017 by Kate Smith

u-blox has released the world's smallest Cat M1 module to date.

This News Brief takes a look at the smallest Cat M1 module on the market, the SARA-R404M from u-blox, which just got certified.

A Brief Intro to Cat M1 LTE

Category M1 LTE is a network technology developed by Verizon Wireless (PDF). Verizon, which had previously led the charge on adopting LTE and Cat 1 LTE, announced that it wanted to begin deploying Cat M1 by the end of 2016. Both Verizon and AT&T created pilot programs last year but Verizon reportedly launched the first Cat M1 nationwide network in March, covering 2.4 million square miles.

Cat M1 was designed with the express intention of allowing for better IoT connections, focusing on power efficiency and lower throughput than its predecessors. It also has better penetration through walls, floors, and the ground, allowing connectivity in previously inaccessible areas.

One of the things that could make Cat M1 a very big deal is that it's purposefully low-cost. This commitment to affordability could possibly break down the remaining barriers between everyday tech and IoT connectivity. In effect, Cat M1 is competing for the future of the IoT with Wi-Fi, Bluetooth, Z-Wave, and Zigbee (which is embroiled in its own competition, primarily with Thread). 

You can compare Cat M1 to Cat 1 in the table below:


Cat M1's specs. The corresponds to the following note: "1 Single antenna is available for non-mission critical and non-VoLTE applications." Image courtesy of Verizon Wireless.

The SARA-R404M Module

2017 is a good year for "World's Smallest" records so far. That trend continues as u-blox, a chip developer and distributor, has jumped into the LTE Cat M1 field with the smallest module yet: the SARA-R404M

The SARA-R404M module allows for compact machine-to-machine (M2M) connectivity that's vital for IoT applications. u-blox claims that the module can contribute to achieving 10 years of battery life by combining PSM (power save mode) with eDRX (extended discontinuous reception) technology.


The SARA-R404M. Image courtesy of u-blox.



  • 96-pin LGA
  • 16.0 x 26.0 x 2.4 mm 
  • <3g
  • Power
    • Uses 3.8 V nominal power supply with a range of 3.3 V to 4.3 V
    • Consumes
      • 125 mA when at max connected power
      • 120 mA when connected at 18 dBm
      • 115 mA when connected at 12 dBm
      • 105 mA when connected at 0 dBm
      • 9 mA when in idle mode
      • 9 μA when in power save mode
  • Interfaces:
    • Serial: 1 UART, 1 USB 2.0, 1 SDIO, 1 DDC, 1 SPI
    • Up to six configurable GPIOs
    • Supports 1.8 V and 3 V SIM

Read more specifics in the SARA-R404M product summary (PDF).

Other LTE Cat M1 Modules

The SARA-R404M is not the first of its kind, though it is the smallest. Already on the market is a host of Cat M1 modules to give designers access to this burgeoning network.

One example is the Cinterion EMS31 from Gemalto, launched in January. Gemalto claimed that the EMS31 was the first LTE Cat M1 chipset designed for IIoT (Industrial IoT) applications, focusing on reliability rather than speed with LPWA (low-power, wide-area) technology.

Also already available is the Monarch SoC from Sequans, certified by Verizon in January of this year. The Monarch chipset is the basis for NimbeLink's Skywire embedded modems


The NimbeLink Skywire module. Image courtesy of NimbeLink (PDF)


Verizon also named Ericsson, Nokia, Sierra Wireless, Telit, and Altair as partners in developing Cat M1 chips. 


Have you worked with any of this Cat M1 hardware? Let us know about your experiences in the comments below!