Reference Design For Power Supply; Requirements For Voltage Stability - Quectel EG915U Series Hardware Design

LTE Standard Module Series
91, 100, 101, 102

3.4.2. Reference Design for Power Supply

The power design for the module is very important, as the performance of the module largely depends on
the power source. The power supply of the module should be able to provide sufficient current of 3.0 A at
least. If the voltage drops between input and output is not too high, it is suggested that an LDO should be
used to supply power to the module. If there is a big voltage difference between the input source and the
desired output (VBAT), a buck converter is recommended.
The following figure illustrates a reference design for +5 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.
MIC29302WU
DC_IN VBAT
2 4
IN OUT
100K
51K 1 %
470R
4.7K
470 μF 100 nF
470 μF
100 nF
47K
VBAT_EN
47K
1 %
Figure 6: Reference Design of Power Supply

3.4.3. Requirements for Voltage Stability

The power supply range of the module is from 3.3 V to 4.3 V. Please make sure the input voltage will
never drop below 3.3 V.
Burst Burst
Transmission Transmission
VBAT
Ripple
Drop
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