Quectel EG25-GL, Проектирование аппаратного обеспечения

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LTE Standard Module Series
EG25-GL_Hardware_Design 34 / 96
Module
VBAT_RF
VBAT_BB
VBAT
C1
C6 C7 C8
+
+
C2
C5
C3 C4
D1
4.5 V 100
μ
F
100 nF 33 pF 100 pF 100
μ
F 100 nF 33 pF 10 pF
Figure 8: Star Structure of the Power Supply
3.3.3 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 should be able to provide sufficient current up to 2.0 A at least. If the
voltage drop between the input and output is not too high, it is suggested that an LDO should 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 +5.0 V input power source. The typical output of the
power supply is about 3.8 V and the maximum load current is 3.0 A.
DC_IN
MIC29302WU
IN OUT
E
N
G
N
D
A
D
J
2 4
1
3 5
VBAT
100K
47K
470R
51K
1%
1%
4.7K
47K
VBAT_EN
470
μ
F
470
μ
F 100 nF
100 nF
Figure 9: Reference Circuit of Power Supply