Specifications

WM_PRJ_Q2501_PTS_002 - 001
March 2004
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3.3.4 SIM interface
3.3.4.1 SIM 3V management
The SIM interface controls a 3 V SIM card only.
To support 1.8 V/3 V or 3 V/5 V SIM cards, an external SIM driver (specific level
shifter) is required (refer to paragraphs 3.3.4.2 and 3.3.4.3).
It is recommended to add Transient Voltage Suppressor diodes (TVS) on the
signal connected to the SIM socket in order to prevent any ElectroStatic
Discharge.
TVS diodes with low capacitance (less than 10 pF) have to be connected on
SIM_CLK and SIM_DATA signals to avoid any disturbance of the rising and
falling edge.
These types of diodes are mandatory for the Full Type Approval. They shall be
placed as close as possible to the SIM socket.
The following references can be used: DALC208SC6 from ST Microelectronics.
Typical implementation with SIM detection:
SIM_VCC 1
SIM_RST 2
SIM_DATA 7
SIM_PRES 8
VCC
RST
CLK
CC4
GND
VPP
I / O
CC8
GND
VCC 4
5
GND
100
k
Ω
C
100 nF
470pf
SIM_CLK 3
GND
GND
(1)
(2)
(1) Recommended components: DALC208SC6 (SGS-THOMSON).
(2) Recommended components: ESDA6V1SC6 (ST).
Figure 16: Example of 3V SIM Socket implementation