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LTE-A Module Series
EG18 Hardware Design
EG18_Hardware_Design 38 / 104
3.5.3. Reference Design for Power Supply
Power design for the module is very important, as the performance of the module largely depends on the
power source. The power supply of EG18 should be able to provide sufficient current up to 2A at least. If
the voltage drop between the input and output is not too high, an LDO is suggested to be used to supply
power for the 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 the power supply.
The following figure shows a reference design for +5V input power source. In this design, output of the
power supply is about 3.8V and the maximum load current is 3A.
DC_IN
MIC29302WU
IN
OUT
E
N
G
N
D
A
D
J
2
4
1
3
5
VBAT
100nF
470
μ
F
100nF
100K
47K
470
μ
F
470R
51K
1%
1%
4.7K
47K
VBAT_EN
Figure 10: Reference Circuit of Power Supply
To avoid damages to the internal flash, please do not switch off the power supply directly when the
module is working. Only after the module is shut down by PWRKEY or AT command can the power
supply be cut off.
3.5.4. Monitor the Power Supply
AT+CBC
command can be used to monitor the voltage value of VBAT_BB. For more details, please refer
to
document [3]
.
NOTE