Smart Wi-Fi Module Series
SC20-WL Hardware Design
SC20-WL_Hardware_Design
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The following figure shows a reference design for +5V input power source which adopts an LDO
(MIC29302WU) from MICREL. The typical output voltage is 3.8V and the maximum rated current is 3.0A.
DC_IN
C1
C2
MIC29302WU
U1
IN
OUT
E
N
G
N
D
A
D
J
2
4
1
3
5
VBAT
100nF
C3
470uF
C4
100nF
R2
100K
47K
R3
470uF
470R
51K
R4
R1
1%
1%
Figure 5: Reference Circuit of Power Supply
1. It is suggested to switch off the power supply for module in
abnormal state, and then switch on the power to restart the module.
2. The module supports battery charging function by default. If
the above power supply design is adopted, please make sure the charging function is disabled by
software or connect VBAT to Schottky diode in series to avoid the reverse current to the power
supply chip.
3.5. Turn on and off Scenarios
3.5.1. Turn on Module Using the PWRKEY
The module can be turned on by driving PWRKEY pin to a low level for at least 1.6s. PWRKEY pin is
pulled to 1.8V internally. It is recommended to use an open drain/collector driver to control the PWRKEY.
A simple reference circuit is illustrated in the following figure.
NOTES