Monitor The Power Supply; Turn On And Off Scenarios; Turn On Module Using The Pwrkey - Quectel UC20 Hardware Design

2A at least. If the voltage drop between the input and output is not too high, it is suggested to use a LDO
to supply power for module. If there is a big voltage difference between the input source and the desired
output (VBAT), a buck converter is preferred to be used as a power supply.
The following figure shows a reference design for +5V input power source. The designed output for the
power supply is about 3.8V and the maximum load current is 3A.
DC_IN
C1
470uF

3.6.4. Monitor the Power Supply

You can use the AT+CBC command to monitor the VBAT_BB voltage value. For more details, please
refer to document [1].

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 7: PWRKEY Pin Description
Pin Name Pin No.
PWRKEY
When UC20 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.
After STATUS pin (require external pull-up) outputting a low level, PWRKEY pin can be released. A simple
UC20_Hardware_Design
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MIC29302WU
2
IN
R1
51K
C2
100nF
Figure 8: Reference Circuit of Power Supply
Description
21 Turn on/off the module.
U1
4
OUT
R2
100K
1%
R4
470R
R3
47K
1%
DC Characteristics
V max = 2.1V
IH
V min = 1.3V
IH
V max = 500mV
IL
Confidential / Released
UMTS/HSPA Module Series
UC20 Hardware Design
VBAT
C3 C4
470uF 100nF
Comment
Pull-up to 1.8V internally
with 200kΩ resistor.
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