LTE Module Series
EC25 Mini PCIe Hardware Design
EC25_Mini_PCIe_Hardware_Design Confidential / Released 18 / 42
3.3. Power Supply
The following table shows pin definition of VCC_3V3 pins and ground pins.
Table 5: Definition of VCC_3V3 and GND Pins
The typical supply voltage of EC25 Mini PCIe is 3.3V. In the 2G networks, the input peak current may
reach to 2.7A during the transmitting time. Therefore, the power supply must be able to provide enough
current, and a bypass capacitor of no less than 470µF with low ESR should be used to prevent the
voltage from dropping.
The following figure shows a reference design of power supply. The precision of resistor R2 and R3 is 1%,
and the capacitor C3 needs a low ESR.
LDO_IN
C1
C2
MIC29302WU
U1
IN
OUT
E
N
G
N
D
A
D
J
2
4
1
3
5
VCC_3V3
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 3: Reference Design of Power Supply
Pin No.
Pin Name
I/O
Power Domain
Description
2, 39, 41, 52
VCC_3V3
PI
3.0~3.6V
3.3V DC supply
4, 9, 15, 18, 21,
26, 27, 29, 34, 35,
37, 40, 43, 50
GND
Mini card ground
Quectel
Confidential
