Smart LTE Module Series
SC650T Hardware Design
SC650T_Hardware_Design 40 / 131
the structure of the power supply.
Module
VDD_RF
VBAT
VBAT
C1
100uF
C6
100nF
C7
33pF
C8
10pF
+
+
C2
100nF
C5
NM
C3
33 pF
C4
10pF
D1
Figure 3: Star Structure of Power Supply
3.4.3. Reference Design for Power Supply
The power design for the module is very important, as the performance of module largely depends on the
power source. The power supply of SC650T should be able to provide sufficient current up to 3A at least.
By default, it is recommended to use a battery to supply power for SC650T. But if battery is not intended
to be used, it is recommended to use a regulator for SC650T. If the voltage difference between the input
and output is not too high, it is suggested to use an LDO 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 which adopts an LDO
(MIC29502WU) from MICROCHIP. The typical output voltage is 3.8V and the maximum rated current is
5.0A.
DC_IN
C1
C2
MIC29502WU
U1
IN
OUT
E
N
G
N
D
A
D
J
2
4
1
3
5
VBAT
100nF
C3
470uF
C4
100nF
R2
100K
47K
R3
470uF
470R
51K
R4
R1
1%
1%
Figure 4: Reference Circuit of Power Supply