Quectel Wireless Solutions Company Limited 201404UC15M User Manual
UMTS/HSDPA Module Series
UC15 Mini PCIe Hardware Design
UC15_Mini_PCIe_Hardware_Design Confidential / Released 21 / 40
UC15 Mini PCIe supports 1.8V and 3.0V USIM cards. The following figure shows the reference design of
the 6-pin USIM card.
Figure 6: Reference Circuit of the 6 Pin USIM Card
In order to enhance the reliability and availability of the USIM card in your application, please follow the
criteria below in the USIM circuit design:
Keep layout of USIM card as close to the module as possible. Assure the length of the trace as less
than 200mm as possible.
Keep USIM card signal away from RF and power supply alignment.
The decouple capacitor of USIM_VDD should be less than 1uF and must be close to USIM
connector.
To avoid cross-talk between USIM_DATA and USIM_CLK, keep them away from each other and
shield them with surrounding ground.
In order to offer good ESD protection, it is recommended to add TVS such as WILL
(http://www.willsemi.com) ESDA6V8AV6. The 22Ω resistors should be added in series between the
module and USIM card so as to suppress the EMI spurious transmission and enhance the ESD
protection. The 33pF capacitors are used for filtering interference of EGSM900. Please note that the
USIM peripheral circuit should be close to the USIM connector.
The pull-up resistor on USIM_DATA line can improve anti-jamming capability when long layout trace
and sensitive occasion are applied.
10
USIM_DATA
IO
USIM/SIM data signal.
1.8V/3.0V
12
USIM_CLK
DO
USIM/SIM clock signal.
1.8V/3.0V
14
USIM_RST
DO
USIM/SIM reset signal.
1.8V/3.0V