SIM900A 데이터 시트보기 (PDF) - Unspecified
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SIM900A Datasheet PDF : 58 Pages
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SIM900 Hardware Design
3 Application Interface
SIM900A is equipped with a 68-pin SMT pad that connects to the cellular application platform. Sub-interfaces
included in these SMT pads are described in detail in following chapters:
z Power supply (please refer to Chapter 3.3)
z Serial interfaces (please refer to Chapter 3.8)
z Analog audio interfaces (please refer to Chapter 3.9)
z SIM interface (please refer to Chapter 3.10)
Electrical and mechanical characteristics of the SMT pad are specified in Chapter 5.
3.1 SIM900A Pin Description
Table 5: Pin description
Power Supply
PIN NAME I/O
VBAT
I
VRTC
I/O
DESCRIPTION
DC CHARACTERISTICS
3 VBAT pins are dedicated to
connect the supply voltage.
The power supply of
SIM900A has to be a single
voltage source of VBAT=
3.4V...4.5V. It must be able
to provide sufficient current
in a transmit burst which
typically rises to 2A
Vmax= 4.5V
Vmin=3.4V
Vnorm=4.0V
Current input for RTC when
the battery is not supplied for
the system.
Current output for backup
battery when the main
battery is present and the
backup battery is in low
voltage state.
Vmax=3.15V
Vmin=2.0V
Vnorm=3.0V
Iout(max)= 300uA
Iin=2 uA
VDD_EXT O 2.8V output power supply
SIM900_HD_V1.01
Vmax=2.95V
Vmin=2.70V
Vnorm=2.80V
17
COMMENT
If the RTC
function is
enabled, a
battery
or
capacitor
should
be
connected with
the VRTC pin.
Otherwise the
VRTC pin can
be keep open.
If unused, keep
open.
26.12.2009
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