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This document is the sole and exclusive property of WAVECOM. Not to be distributed or divulged
without prior written agreement.
WM_PRJ_Q24NG_PTS_002-001 June
2006
3.2.6 SIM
interface
3.2.6.1 SIM 3V management
The Q24NG SIM interface automaticaly detects and manages a 1.8V and
3V SIM card.
It is also possible to manage 1V8V/3V or 3V/5V SIM cards by using an
external voltage level shifter controlled by the GPO0 output signal (refer to
§ 3.2.6.2 and § 3.2.6.3).
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
Warning:
These types of diodes are mandatory if the SIM holder is externally
accessible. They shall be placed as close as possible to the SIM socket.
The following references can be used: DALC208SC6 and ESDA-6V1SC6
from
ST Microelectronics.
Typical implementation with SIM detection:
ESDA-6V1SC6
(ST)
DALC208SC6 (ST)
100nF
100K
470pF
VCC Q24NG
(2V8)
SIMVCC
SIMDAT
SIMRS
SIMCLK
GND
Not Connected
SIM
(1) VCC
(2) RST
(3) CLK
(4) CC4
(5) GND
(6) VPP
(7) I/O
(8) CC8
As close as possible to the SIM HOLDER
ESD
As close as possible to the SIM HOLDER
Q24NG
Figure 8: Example of 3V SIM Socket implementation
