UMTS/HSPA Module Series
UG95 Hardware Design
UG95_Hardware_Design Confidential / Released 41 / 72
If you do not need the USIM card detection function, keep USIM_PRESENCE unconnected. The
reference circuit for using a 6-pin USIM holder is illustrated as the following figure.
Module
USIM_VDD
USIM_GND
USIM_RST
USIM_CLK
USIM_DATA
22R
22R
22R
100nF
USIM holder
GND
ESD
33pF 33pF 33pF
VCC
RST
CLK
IO
VPP
GND
GND
15K
USIM_VDD
Figure 24: Reference Circuit of the 6-Pin USIM Card
In order to enhance the reliability and availability of the U
SIM card in customer’s application, please follow
the criteria below in the USIM circuit design:
Keep layout of USIM card as close as possible to the module. Assure the length of the trace is as less
than 200mm as possible.
Keep USIM card signal away from RF and VBAT alignment.
Assure the ground between module and USIM holder short and wide. Keep the 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 be near to USIM holder.
To avoid cross-talk between USIM_DATA and USIM_CLK, keep them away with each other and
shield them with surrounded ground.
In order to offer good ESD protection, it is recommended to add TVS such as WILL
). The 22Ω resistors should be added in series between the module and the
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 holder.
The pull-up resistor on USIM_DATA line can improve anti-jamming capability when long layout trace
and sensitive occasion is applied, and should be placed close to the USIM holder.
Quectel
Confidential
