IoT (Internet of Things) devices require specialized SIM (Subscriber Identity Module) form factors to enable communication and connectivity. The choice of the right form factor depends on the device's size and technical specifications. Let's explore the various SIM form factors and compare their characteristics.
1FF. The first form factor, measuring 85.6mm × 53.98mm × 0.76mm, is rarely used today due to its large size.
2FF/Mini-SIM. This is the largest available SIM size, measuring approximately 25mm long by 15mm wide. It is commonly found in large IoT/M2M devices like vehicles, vending machines, and payment points.
3FF/Micro-SIM. Smaller than the Mini-SIM, the Micro-SIM measures around 15mm long by 12mm wide. It is designed to fit into medium to small IoT/M2M devices such as tablets or smart health devices.
4FF/Nano-SIM. The Nano-SIM is the smallest removable form factor in the market. It is approximately 40% smaller than the Micro-SIM, measuring only 12.3mm long by 8.8mm wide and thinner by about 15%. This form factor is ideal for small devices like trackers.
MFF2 or IoT SIM Chip. The SIM Chip, often referred to as MFF2, has a form factor of 5mm x 6mm x 1mm. It can be equipped with eUICC capabilities, similar to removable SIMs. The MFF2 IoT SIM Chip is suitable for applications that require resistance to vibrations, movement, moisture, and corrosion. It finds applications in sectors like utilities and consumer electronic devices. A SIM chip can be found in robust/industrial Grade designed to withstand tougher conditions.
iSIM (Integrated SIM). iSIM is a relatively new SIM technology that goes beyond a form factor. It is designed into the module as part of a System on Chip (SoC), eliminating the need for separate hardware. iSIM offers advantages such as smaller device size, lower energy consumption, simplified logistics, reduced costs, and a decreased carbon footprint.
TRE (Tamper Resistant Element). In TRE-based iSIM, the network authentication keys are protected by a hardware-based security feature, similar to a discrete SIM card. This ensures the highest level of security for IoT devices.
TEE (Trusted Execution Environment). TEE is a segregated part of a chip or module that can be accessed externally. It provides a lower level of security compared to TRE but still offers enhanced protection for IoT applications.
Soft SIM. Soft SIM refers to IoT SIM functionality that can only be accessed via software, without dedicated hardware for its placement. Soft SIMs are more flexible but may offer a lower level of security compared to TRE and TEE.
eUICC should not be confused with a form factor as it is first a capability to shift from one MNO profile to another without physical interaction with a SIM. Moreover, the term ‘eSIM’ that is often associated with eUICC, indeed goes beyond this capability and relates to the MFF2 form factor. It can be applied to any SIM format above – 2FF, 3FF, 4FF, MFF2, iSIM. Find more details here.
WLCSP (Wafer-Level Chip-Scale Packages) and CSP (Chip-Scale Packages) are used in various IoT applications where compact size, lightweight design, and efficient space utilization are critical. These advanced packaging techniques occupy less than 25% of the MFF2 area, resulting in cost, space, and energy-efficient solutions for IoT devices. The use cases of such technologies include wearable electronic devices, GPS trackers, Industrial applications, smart thermostats, smart city.
