Product Info

LTE Module Series
EG91 Hardware Design
EG91_Hardware_Design 36 / 93
diode with low reverse stand-off voltage V
RWM
, low clamping voltage V
C
and high reverse peak pulse
current I
PP
should be used. The following figure shows the star structure of the power supply.
Module
VB AT_ RF
VB AT_BB
VB AT
C1
100uF
C6
100nF
C7
33pF
C8
10pF
+
+
C2
100nF
C5
100uF
C3
33pF
C4
10pF
D1
WS4.5D3HV
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