Power On/Off Gsm Part; Power On Gsm - SIM Tech SIMCom SIM868 Series Hardware Design

5.3. Power on/off GSM Part

5.3.1.

Power on GSM

Customer can power on GSM by pulling down the PWRKEY pin for at least 1 second and then release. This pin
is already pulled up to 3V in the module internal, so external pull up is not necessary. Reference circuits are
shown as below.
Turn on/off
impulse
The power on timing is illustrated as Figure 15:
VBAT
PWRKEY
(INPUT)
VDD_EXT
STATUS
Serial Port
When power on procedure is completed, GSM will send following URC to indicate that the module is ready to
SIM868_Series_Hardware_Design_V1.06
PWRKEY
4.7K
47K
Figure 13: Powered on/off GSM using transistor
PWRKEY
Figure 14: Powered on/off GSM using button
T>1.5s
V <0.7V
IL
T>62ms
Undefind
Figure 15: Timing of power on GSM
Smart Machine Smart Decision
3V
100K
Power
on/off logic
1K
GSM
3V
100K
Power
on/off logic
1K
GSM
t>1s
t>3.2s
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Active
2017-07-13