Reference Design For Power Supply - Quectel EG91 Series Hardware Design

LTE Module Series
EG91 Hardware Design
diode with low reverse stand-off voltage V , low clamping voltage V and high reverse peak pulse
RWM C
current I should be used. The following figure shows the star structure of the power supply.
PP
VBAT
VBAT_RF
VBAT_BB
+
+
C5
C4 C6 C7 C8
C2 C3
C1
D1
100nF 10pF
100uF 33pF 100uF 100nF 33pF 10pF
WS4.5D3HV
Module
Figure 8: Star Structure of the Power Supply

3.6.3. Reference Design for Power Supply

Power design for the module is very important, asthe performance of the module largely depends on the
power source. The power supply 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, it is suggested that an LDO should be usedto
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. The typicaloutput ofthe power
supply is about 3.8V and the maximum load current is 3A.
Figure 9: Reference Circuit of Power Supply
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