User's Manual

Smart Machine Smart Decision
SIM5320A_Hardware Design_V1.01 2011-2-29
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Table 7: Power on timing
Parameter Description Time value Unit
Ton The time to pull POWER_ON down to power on 64< Ton<180 ms
TpD+ The time to indicate connecting with the network >5.5 s
Tpw+
The time to indicate the module is powered on
completely
>4.5 s
Tuart The time to enable UART >4.7 s
Tusb The time to enable USB >9 s
Automatic power on
If user needs to power on SIM5320A automatically whenever the VBAT pins are connected to the power
supply, then POWER_ON pin is just pulled to ground by a resistance in circuit directly. The following is
the reference circuit.
10 K
POWER _ON
Power
on
/off logic
200K
1.8V
MODULE
R1
RESET
Reset impulse
V
IL
<0.3V
50ms<t<200ms
VBAT
RESET
( Input)
Figure 18: Application circuit
Note: After automatically powering on the module by pulling down POWER_ON pin to ground anytime, USB/UART may
not communicate normally with host, so it is suggested that SIM5320A should be reset by RESET pin.
3.2.2 Power off Sequence
The following methods can be used to power down SIM5320A. These procedures will make module
disconnect from the network and allow the software to enter a safe state, and then save data before
completely powering the module off.