SIM900D Hardware Design
RL=32 Ohm
THD=0.1%
-
91
-
mW
RL=32 Ohm
THD=1%
-
96
-
mW
3.11 SIM Card Interface
3.11.1 SIM Card Application
That can be use AT Command to get information in SIM card. For more information, please refer to
document
[1].
The SIM interface supports the functionality of the GSM Phase 1 specification and also supports the functionality
of the new GSM Phase 2+ specification for FAST 64 kbps SIM (intended for use with a SIM application
Tool-kit).
Both 1.8V and 3.0V SIM Cards are supported.
The SIM interface is powered from an internal regulator in the module having normal voltage 3V. All pins reset
as outputs driving low. Logic levels are as described in table
Table15: Pin definition of the SIM interface
Pin Name
Pin Number
Function
SIM_VDD
9
SIM Card Power supply, it can identify automatically the SIM
Card power mode
，
one is 3.0V±10%, another is 1.8V±10%.
Current is about 10mA.
SIM_DATA
6
SIM Card data I/O
SIM_CLK
7
SIM Card Clock
SIM_RST
8
SIM Card Reset
Following is the reference circuit about SIM interface. Recommend an Electro-Static discharge device ST
(
) ESDA6V1W5 or ON SEMI (
) SMF05C for “ESD ANTI”. The 22
Ω
resistors
showed in the following figure should be added in series on the IO line between the module and the SIM card for
protecting the SIM I/O port. The pull up resistor (about 15K
Ω
) on the SIM_DATA line already added in the
module. Note that the SIM peripheral circuit should be close to the SIM card socket.
The reference circuit about 6 pins SIM card illustrates as following figure.
SIM900D_HD_V1.02
09.04.2010
44
