Sim Card Interface; Sim Card Application - SimCom SIM900B Hardware Design

Table 6: Microphone Input Characteristics
Parameter
Working Voltage
Working Current
External Microphone Load Resistance
Internal biasing DC Characteristics
Differential input THD
voltage F=1KHz; pre-amp
gain = 20 dB;
PGA gain = 14 dB
THD
F=1KHz;pre-amp
gain = 0 dB; PGA
gain = 0 dB
Table 7: 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)
3.8

SIM Card Interface

3.8.1

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 cards 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.
SIM900B_Hardware Design_V2.01
Min
1.2
200
1.2
<1% at
<5% at
Min
-
-
Typ Max
1.5 2.0
500
2.2
2.5
15.9
740
Typ Max
91 -
96 -
1.1
2.2
(www.st.com ) ESDA6V1W5 or ON SEMI
26
Smart Machine Smart Decision
Unit
V
uA
kΩ
V
mVrms
mVrms
Unit
mW
mW
Vpp
Vpp
2012-05-07