User's Manual

UMTS/HSPA Module Series
UC20 User Manual
UC20_Hardware_Design Confidential / Released 33 / 84
reference circuit is illustrated in the following figure.
Turn on pulse
PWRKEY
4.7K
47K
≥ 100ms
Figure 9: Turn on the Module Using Driving Circuit
The other way to control the PWRKEY 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.
PWRKEY
S1
Close to S1
TVS
Figure 10: Turn on the Module Using Keystroke
The turn on scenarios is illustrated as the following figure.