Quectel EC2 Series User Manual

LTE Module Series
EM05 Hardware Design
EM05_Hardware_Design Confidential / Released 23 / 59
Module
VCC
C1
220uF
+
D1
C2
1
uF
C3
100nF
C4
33pF
C5
10pF
VCC
Figure 6: Reference Circuit of VCC
3.5.2. 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 is capable of providing 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 used to supply
power for the module. If there is a big voltage difference between the input source and the desired output
(VCC), 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 typical output of the power
supply is about 3.3V and the maximum load current is 3A.
LDO_IN
C1
C2
MIC29302WU U1
IN
OUT
EN
GND
ADJ
2 4
1 3 5
3.3V
100nF
C3
470uF
C4
100nF
R2
82K 1%
47K 1%
R3
470uF
470R
51K
R4
R1
MCU_POWER
_ON/OFF
47K
4.7K
R5
R6
C5
C6
33pF
10pF
TVS
D1
Figure 7: Reference Design of Power Supply
In order to avoid damaging internal flash, please do not switch off the power supply when the module
works normally. It is suggested that the power supply can be cut off after pulling down RESET# for about
100ms.
NOTE
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Quectel EC2 Series Specifications

General

Brand	Quectel
Model	EC2 Series
Category	Control Unit
Language	English