SimCom SIM900 Hardware Design

SIM900 Hardware Design
VDD_EXT O 2.8V output power supply Vmax=2.95V
Vmin=2.70V
Vnorm=2.80V
Iout(max)= 10mA
If unused, keep
open.
GND Ground
Power on or power off
PIN NAME I/O DESCRIPTION DC CHARACTERISTICS
PWRKEY I Voltage input for PWRKEY.
PWRKEY should be pulled
low to power on or power off
the system. The user should
drive the PWRKEY to low
level voltage for a short time
when power on or power off
the system because the
system need margin time in
order to assert the software.
VILmax=0.15*VDD_EXT
VIHmin=0.85* VDD_EXT
VImax=VDD_EXT
VILmin= 0V
It is already
pulled up.
PWRKEY_O
UT
O Connecting PWRKEY and
PWRKEY_OUT for a short
time then release also can
power on or power off the
module.
VOHmin= VDD_EXT-0.1V
VOLmax=0.1V
VOHmax= VDD_EXT
VOLmin= 0V
Audio interfaces
PIN NAME I/O DESCRIPTION DC CHARACTERISTICS COMMENT
MIC_P
MIC_N
I Positive and negative voice
band input
Audio DC Characteristics refer to
chapter 3.9
If unused keep
open
SPK_P
SPK_N
O Positive and negative voice
band output
If unused keep
open
LINEIN_R
LINEIN_L
I Line input If unused keep
open
GERNERAL PURPOSE input/output
PIN NAME I/O DESCRIPTION DC CHARACTERISTICS COMMENT
STATUS O Indicate working status If unused keep
open
NETLIGHT O Indicate net status If unused keep
open
DISP_DATA I/O
DISP _CLK O
DISP _CS O
DISP _D/C O
Display interface
VILmax=0.15 *VDD_EXT
VIHmin=0.85*VDD_EXT
VILmin= 0V
VIHmax= VDD_EXT
VOHmin= VDD_EXT-0.1V
VOLmax=0.1V
VOHmax= VDD_EXT
VOLmin= 0V
If unused keep
open
SIM900_HD_V1.05 06.23.2010
18

SimCom SIM900 Specifications

General

Brand	SimCom
Model	SIM900
Category	Modem
Language	English