Circuit Protection of SIM Socket
The signals used in the Subscriber Identification Module (SIM) circuit include Data, Clock and Reset. Since the SIM card can be removed by the user, there is an ESD to the SIM interface socket.
A single, space efficient TVS diode array can also be used. The SP3002-04UTG is shown; if a device with greater ESD capabilities is desired, the SP1011-04UTG can be used. MLA Series Multilayer Varistors (MLVs) or SP0503 series SPA TVS Diode Arrays may also be used.
The IEC 61000-4-2 will be the most appropriate standard that applies for this port. It supplies a test method for verifying that the end product is not susceptible to ESD events.