Gsm Application Interface; Pin Description - SimCom SIM548C HD V1.01 Hardware Design

SIM548C Hardware Design

3 GSM application interface

All hardware interfaces except RF interface that connects SIM548C to the customers' cellular
application platform is through a 60-pin 1.27mm pitch board-to-board connector. Sub-interfaces
included in this board-to-board connector are described in detail in following chapters:
Power supply and charging control
GSM serial interface
Two analog audio interfaces
SIM interface
Electrical and mechanical characteristics of the board-to-board connector are specified in Chapter
6. There are also ordering information for mating connectors.

3.1 Pin description

Table 5: Board-to-Board connector pin description
Power Supply
PIN NAME
VBAT
VRTC
VCHG
SIM548C_HD_V1.01
I/O DESCRIPTION
4 VBAT pins of the board-to-board
connector are dedicated to connect
the supply voltage. The power supply
of the GSM part of 548C has to be a
single voltage source of VBAT=
3.4V...4.5V. It must be able to provide
sufficient current in a transmitting
burst which
2A.mostly. These 4 pins are voltage
input
RTC current input from the backup
I/O
battery when the VBAT is not
supplied for the system.
Current output to backup battery
when the main battery is present and
the backup battery is low voltage
state.
Voltage input for the charge circuit;
I
making the system detect the charger.
19
typically rises to
DC CHARACTERISTICS
Vmax= 4.5V
Vmin=3.4V
Vnorm=4.0V
Vmax=2.0V
Vmin=1.2V
Vnorm=1.8V
I = 20uA
out(max)
I =5 uA
in
Vmax=5.25V
Vmin=1.1 * VBAT
Vnorm=5.1V
09.05.2008