Shanghai SIMCom Wireless Solutions Limited 8PSA301 ユーザーズマニュアル
Smart Machine Smart Decision
10
4
Crownpo
CDZ55C5V1SM
500mW
0805
Power on/off
Power on
Users can power on SIM8905A by pulling down the PWRKEY pin for more than 2 second then release. This pin
is already pulled up to 1.8V internally, so external pull up is not necessary. Reference circuits are shown as below:
is already pulled up to 1.8V internally, so external pull up is not necessary. Reference circuits are shown as below:
4.7K
47K
PWRKEY
R
1.8V
1K
PMU
Module
Figure 7: Powered on/down module using transistor
PWRKEY
1K
Module
R
1.8V
PMU
Figure 8: Powered on/down module using button
The power on sequence is illustrated in Figure9
Software Controlled
VBAT
PWRKEY
Others
t>2s
LDO5_1V8
LDO6_1V8
250us
175ms