Quectel UG89 Hardware Design page 27

UMTS/HSPA+ Module Series
UG89 Hardware Design
PWRKEY
≥ 500ms
4.7K
10nF
Turn-on pulse
47K
Figure 6: Reference Circuit of Turing on the Module Using Driving Circuit
The other way to control the PWRKEY is using a button directly. When pressing the key, an electrostatic
strike may generate from the finger. Therefore, a TVS component is indispensable to be placed nearby
the button for ESD protection. A reference circuit is shown in the following figure.
S1
PWRKEY
TVS
Close to S1
Figure 7: Reference Circuit of Turing on the Module Using Keystroke
The timing of turning on the module is illustrated in the following figure.
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