User's Manual

UMTS/HSPA Module Series
UG95 Hardware Design
UG95_Hardware_Design Confidential / Released 27 / 67
When UG95 is in power down mode, it can be turned on to normal mode by driving the PWRKEY pin to a
low level at least 100ms. It is recommended to use an open drain/collector driver to control the PWRKEY.
You can monitor the level of the STATUS pin to judge whether the module is turned on or not. The
STATUS pin output a high level, after UG95 is turned on. A simple reference circuit is illustrated in the
following figure.
Turn on pulse
PWRKEY
4.7K
47K
≥ 100ms
Figure 7: 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 8: Turn on the Module Using Keystroke
The turn on scenarios is illustrated as the following figure.