Quectel EC25 series, Проектирование аппаратного обеспечения

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LTE Module Series
EC25 Mini PCIe Hardware Design
EC25_Mini_PCIe_Hardware_Design Confidential / Released 19 / 42
3.4. USIM Card Interface
The following table shows the pin definition of USIM card interface.
Table 6: USIM Pin Definition
EC25 Mini PCIe supports 1.8V and 3.0V USIM cards. The following figure shows a reference design for a
6-pin USIM card connector.
USIM_VDD
GND
USIM_RST
USIM_CLK
USIM_DATA
22R
22R
22R
100nF
USIM Card Connector
GND
33pF 33pF 33pF
VCC
RST
CLK IO
VPP
GND
GND
33pF
15K
Module
USIM_VDD
Figure 4: Reference Circuit of USIM Card Interface with a 6-Pin USIM Card Connector
In order to enhance the reliability and availability of the USIM card in your application, please follow the
criteria below in USIM circuit design:

Keep layout of USIM card as close to the module as possible. Keep the trace length as less than
200mm as possible.

Keep USIM card signal away from RF and power supply traces.

Keep the trace width of ground and USIM_VDD no less than 0.5mm to maintain the same electric
potential. The decouple capacitor of USIM_VDD should be less than 1uF and must near to USIM
card connector.
Pin No. Pin Name I/O Power Domain Description
8 USIM_VDD PO 1.8V/3.0V Power source for the USIM card
10 USIM_DATA IO 1.8V/3.0V USIM data signal
12 USIM_CLK DO 1.8V/3.0V USIM clock signal
14 USIM_RST DO 1.8V/3.0V USIM reset signal
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