UMTS/HSPA+ Module Series
UG89 Hardware Design
UG89_Hardware_Design 27 / 73
V
IL
≤
0.5V
VBAT
PWRKEY
≥
500ms
RESET_N
STATUS
(DO)
I nactive
Active
UART
NOTE 1
Inactive
Active
USB
≥
≥
≥
VDD_EXT
USB_BOOT
≥
100ms. After this time, the pin can be set
high level by an external circuit.
10s
10s
10s
5ms
About 22ms
About
Figure 8: Timing of Turning on the Module
1. Please make sure that VBAT is stable before pulling down PWRKEY pin. The time between them
is no less than 30ms.
2. PWRKEY can be pulled down directly to GND with a recommended 4.7
kΩ resistor if the module
needs to be powered on automatically and shutdown is not needed.
3.6.2. Turn off the Module
The following procedures can be used to turn off the module:
Using the PWRKEY pin.
Using
AT+QPOWD
command.
NOTES