UMTS/HSDPA Module
UC15 Hardware Design
UC15_Hardware_Design Confidential / Released 25 / 72
3.6.4. Monitor the Power Supply
You can use the “AT+CBC” command to monitor the VBAT_BB voltage value. The voltage is continuously
measured at an interval depending on the operation mode. The displayed voltage (in mV) is averaged
over the last measuring period before the “AT+CBC” command is executed. For more details, please refer
to
document [1].
3.6.5. VDD_EXT
UC15 has a LDO power output, namely VDD_EXT. The VDD_EXT is available and output voltage is 2.6V
by default, rated for 100mA.
The following table shows electronic characteristics of VDD_EXT.
Table 7: Electronic characteristics of VDD_EXT
Symbol
Description
Min
Typ
Max
Unit
VDD_EXT Output
voltage
2.5 2.6 2.7 V
Io Output
current
- - 100 mA
3.7. Turn on and off Scenarios
3.7.1. Turn on Module Using the PWRKEY
The following table shows the pin definition of PWRKEY.
Table 8: PWRKEY Pin Description
Pin Name Pin No.
Description
DC Characteristics
Comment
PWRKEY
18
Turn on/off the module.
V
IH
max = 2.1V
V
IH
min = 1.6V
V
IL
max = 0.3V
Pull-up to 1.8V internally
with 200k
Ω
resistor.
When UC15 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.
After
STATUS pin outputting a high level, module is turned on. A simple reference circuit is illustrated in the
following figure.
