SIM or SIM card is a common name for a smart card which is used to secure access to the mobile telecommunications network. Physically, the SIM is an application running on the Universal Integrated Circuit Card (UICC) and standard SIM form factors are governed by relevant UICC standards defined by ETSI.
Two major UICC types are Removable and M2M.
- A removable UICC is a piece of plastic with embedded contacts and a smart card chip that is inserted into a SIM Slot to connect to the rest of the device.
- An M2M chip is the same smart card chip with contacts packaged as an embedded (non removable) chip that needs to be soldered on the logic board of the device.
Removable UICC form factors
UICC
Standard — ETSI TS 102 221. As per standard, there are:
- ID-1 UICC
- Plug-in UICC
- Mini-UICC
- 4FF
Most commonly used removable SIM cards are Mini-UICC (standard SIM) and 4FF (Nano SIM)
Physical characteristics:
Mini-UICC width 15mm, height 12mm4FF width 12.3mm +/- 0.1mm, height 8.8mm +/1 0.1mm, thickness 0.67 mm +0.03 mm/-0.07 mm
M2M SIM form factors
M2M UICC
Standard — ETSI TS 102 671. As per standard, there are
- MFF1
- MFF2
MFF2 is sometimes referred to as DFN-8, SON-8 or VQFN-8
Physical characteristics:
Width 6mm, height 5mm, thickness 0.85mm
Quality characteristics
Depending on the intended application, vary in
- Operational and storage temperature
- Moisture conditions
- Humidity
- Corrosion
- Vibration
- Shock
- Data retention time
- Minimum updates
Enhanced vibration and shock resistance SIMs are sometimes called “Automotive Grade” SIMs.
Non standard form factors
Form factor optimisation
Outside of ETSI physical UICC standards, a few other miniaturised formats have emerged.
- iUICC — Integrated UICC, where the UICC function is performed by a separate secure core inside a larger chip, e.g. a modem or a
- VQFN32–5x5x0.85 mm
- Miniaturised packages:
- WFWLB-16 2.7x2.5x0.7 mm
- XFWLB-25 2.5x2.9x0.4 mm
- TSNP-10 1.1x1.5x0.37 mm
