Reference Design For Power Supply - Quectel RM502Q-GL Hardware Design

VCC (3.7 V Typ.)
+
+
D1
5.1 V

3.3.2. Reference Design for Power Supply

Power design is critical as the module's performance largely depends on its power source. The power
supply of the module should be able to provide a sufficient current of 3.0 A at least. If the voltage
difference between the input and output is not too big, use an LDO when supplying power for the module.
If there is a big voltage difference between the input source and the desired output (VCC = 3.7 V Typ.), a
buck DC-DC converter is preferred.
The following figure shows a reference design for +5.0 V input power source based on a DC-DC
converter. The typical output of the power supply is about 3.7 V and the maximum load current is 3.0 A.
PWR_IN
+
D1
C1 C2 C3
470 μF
TVS 100 nF 33 pF
R7
4.7k
PWR_EN
R8
47k
RM502Q-GL_Hardware_Design
C2
C4 C6
220 μF
1 μF
100 nF
C1
C3 C5
220 μF
1 μF
100 nF
Figure 6: Reference Circuit for VCC Pins
VIN
VIN
R1
VIN
205k
EN
R2
VFB VSNS
COMP
80.6k
RT/CLK
SS
R3 R4
10k 182k
Q1
NPN
C5 C4 C7
10 nF
NM 10 nF
Figure 7: Reference Design of Power Supply
VCC 2, 4
C8 C10
33 pF 10 pF
GND
3, 5, 11
VCC 70, 72, 74
C7 C9
33 pF 10 pF
27, 33, 39,
GND
45, 51, 57,
71, 73
L1
U1
μ
1.5 H
PH
PH
C6
PH
100 nF
BOOT
PWRGD PWRGD
GND
GND
AGND
EP
VFB
5G Module Series
RM502Q-GL Hardware Design
Module
ET
PMU
PWR_OUT
+
C8 C11
C9 C10
220 μF
100 nF 33 pF 10 pF
R5
383k 1%
R6
100k 1%
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