Sim Card Interface; Sim Card Application - SimCom SIM900D Hardware Design

Table 10: Audio Output Characteristics
Parameter Conditions
RL=32Ω
THD=0.1%
RL=32Ω
THD=1%
Normal
Output swing
Output(SPK)
Voltage
(single ended)
Output swing
Voltage
(differential)
4.8

SIM Card Interface

4.8.1

SIM Card Application

The SIM interface complies with the GSM Phase 1 specification and the new GSM Phase 2+ specification for
FAST 64 kbps SIM card. Both 1.8V and 3.0V SIM card are supported. The SIM interface is powered from an
internal regulator in the module.
It is recommended to use an ESD protection component such as ST
(www.onsemi.com ) SMF05C.The pull up resistor (15KΩ) on the SIM_DATA line is already added in the module
internal. Note that the SIM peripheral circuit should be close to the SIM card socket. The reference circuit of the
8-pin SIM card holder is illustrated in the following figure.
The SIM_PRESENCE pin is used for detection of the SIM card hot plug in. User can select the 8-pin SIM card
holder to implement SIM card detection function. AT command "AT+CSDT" is used to enable or disable SIM
card detection function. For details of this AT command, please refer to document [1].
If the SIM card detection function is not used, user can keep the SIM_PRESENCE pin open. The reference
circuit of 6-pin SIM card holder is illustrated in the following figure.
SIM900D_Hardware Design_V2.02
Min
-
-
Figure 28: Reference circuit of the 8-pin SIM card holder
Typ Max
91 -
96 -
1.1
2.2
(www.st.com ) ESDA6V1W5 or ON SEMI
34
Smart Machine Smart Decision
Unit
mW
mW
Vpp
Vpp
2012-05-07