LTE Standard Module Series
EC20 R2.1 Mini PCIe Hardware Design
EC20_R2.1_Mini_PCIe_Hardware_Design 19 / 51
The host’s USB bus, which is connected with the module’s USB interface, enters suspend state.
3.4.2. Airplane Mode
When the module enters airplane mode, the RF function will be disabled, and all AT commands related to
it will be inaccessible. For more details, please refer to
Chapter 3.10.3
.
3.5. Power Supply
The following table shows pin definition of power supply interface.
Table 6: Definition of Power Supply Interface
The typical supply voltage of EC20 R2.1 Mini PCIe is 3.3V. In the 2G network, the input peak current may
reach 2.7A during the transmitting time. Therefore, the power supply must be able to provide a rated
output current of 2.7A at least, 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 where R2 and R3 are 1% tolerance
resistors and C3 is a low-ESR capacitor.
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 Circuit of Power Supply
Pin Name
Pin No.
I/O
Power Domain
Description
VCC_3V3
2, 39, 41, 52
PI
3.0V~3.6V
Typically 3.3V DC supply
GND
4, 9, 15, 18, 21,
26, 27, 29, 34,
35, 37, 40, 43, 50
Mini card ground