UMTS/HSPA+ Module Series
UC200A-GL_Hardware_Design 30 / 78
Another way to control the PWRKEY is using a button directly. When pressing the button, electrostatic
strike may generate from 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.
PWRKEY
M odule
S1
Close to S1
TVS
Turn-on pulse
Figure 10: Turning on the Module
with a Button
The power up scenario is illustrated in the following figure.
V
IL
≤
0.5 V
VBAT
PWRKEY
≥
500 ms
RESET_N
STATUS
(OD)
I nactive
Active
UART
NOTE 1
Inactive
Active
USB
≥
10 s
VDD_EXT
USB_BOOT
≥
100 ms. After this time, the pin can be set
high level by an external circuit.
About 22 ms
About 5 ms
≥
10 s
≥
10 s
Figure 11:
Power-up Timing