Considerations when choosing MFF2 sim chips


Most of us are familiar with the traditional simcards, which we know as mini, micro and nano simcards, 2FF, 3FF and 4FF respectively. However, for many types of hardware, these sizes are impractical. We will specifically indicate the advantages of solderable simcards, also known as embedded sims (MFF2). These simcards are mounted directly on the printed circuit board (PCB) and cannot be easily removed like the traditional simcards. A 6×5 mm microchip that is soldered onto a printed circuit board.

Advantages of an MFF2 SIM chip

These are the main advantages of MFF2 simcards over traditional simcards:

Smaller size

One of the main reasons for choosing embedded sims is their exceptionally small size, which can be valuable in wearables, for example. At only 6×5 mm, an MFF2 simchip is physically smaller than even a nano simcard.

Cost reduction

Sockets and connectors can be expensive, and many IoT devices need to keep their Bill of Material (BOM) low to make economic sense. Engineers should compare the cost of an MFF2 simcard to the combined cost of a traditional plastic simcard and socket.

Robust construction for IoT devices deployed in harsh environments

Properly formed solder joints are incredibly robust and ensure a solid mechanical attachment of the sim to the circuit board. simcard sockets use spring-loaded contacts that press against the plastic sim’s electrical contacts to make an electrical connection. Drop it or subject it to a high-vibration environment, such as a vehicle, and the contacts may “bounce” off the card and temporarily lose electrical connection. If this happens while the modem is trying to communicate with the card, it will cause communication errors. An MFF2 simcard has no contacts to bounce or oxidize, which can lead to better conductivity.

IoT devices deployed in humid environments

In humid environments it is preferable to use an enclosure to keep the water out, but this is not always possible. Alternatively, you can provide the circuit board with a waterproof insulating coating to prevent moisture from causing a short circuit. However, during application it is critical to limit this coating from sockets and connectors, which requires careful application, masking or barriers. A printed circuit board with an MFF2 SIM card can easily be coated without damaging the SIM card.

IoT devices deployed in warm environments at high temperatures

While there are higher temperature plastic sims, the most common ones simply melt at elevated temperatures. MFF2 simcards are suitable for higher temperatures than plastic simcards. High temperatures are usually found in unvented electronics in hot environments.

Better security

A simcard in a socket can be easily removed once and used in an unauthorized IoT device. A soldered MFF2 sim chip is much more difficult to remove without soldering equipment and not so easy to use in a smartphone or tablet.

Fewer assembly steps

During manufacturing, the labour-intensive simcard installation step is replaced by loading a roll of sim chips into the pick and place robot that places the electronic components on the printed circuit board. Pick and place machines, also known as chip shooters, can place thousands of components per hour.

How to get around the disadvantages of an MFF2 SIM chip?

The main drawback of MFF2 sim chips is that they require more upfront planning to install than their swappable counterparts because they require physical soldering to the circuit board. As a result, the mobile connectivity provider must be selected at the time of manufacture, when all components are soldered onto the PCB at the same time.

For more questions about MFF2 simchips, you can contact us via telephone number 085-0443500 or by e-mail to