UMTS/HSPA Module Series
UG95 Hardware Design
UG95_Hardware_Design Confidential / Released 33 / 72
The other way to control the PWRDWN_N is using a button directly. A TVS component is indispensable to
be placed nearby the button for ESD protection. When pressing the key, electrostatic strike may generate
from finger. A reference circuit is showed in the following figure.
PWRDWN_N
S2
Close to S2
TVS
Figure 14: Turn off the Module Using Keystroke
The emergency shutdown scenario is illustrated as the following figure.
VBAT
PWRDWN_N
≥100
ms
RUNNING
Power-down procedure
OFF
STATUS
Module
Status
Figure 15: Timing of Emergency Shutdown
Use the PWRDWN_N only when turning off the module by the command
AT+QPOWD
or the RESET_N
pin failed.
NOTE
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