
UMTS/HSPA Module Series
UG96 Hardware Design
UG96_Hardware_Design 41 / 76
Module
USIM_VDD
USIM_GND
USIM_RST
USIM_CLK
USIM_DATA
22R
22R
22R
100nF
GND
ESD
33pF 33pF 33pF
VCC
RST
CLK
IO
VPP
GND
GND
15K
USIM_VDD
(U)SIM card connector
Figure 24: Reference Circuit of (U)SIM Interface with a 6-Pin (U)SIM Card Connector
In order to enhance the reliability and availability of the (U)SIM
card in customer’s applications, please
follow the criteria below in (U)SIM circuit design:
⚫
Keep placement of (U)SIM card connector as close to the module as possible. Keep the trace length
as less than 200mm as possible.
⚫
Keep (U)SIM card signal away from RF and VBAT traces.
⚫
Assure the ground between the module and the (U)SIM card connector short and wide. Keep the
trace width of ground no less than 0.5mm to maintain the same electric potential. Make sure the
decouple capacitor between USIM_VDD and USIM_GND less than
1μF and be placed as close to
the (U)SIM card connector as possible.
⚫
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 a TVS diode array with parasitic
capacitance not exceeding 15pF.
The 22Ω resistors should be added in series between the module
and the (U)SIM 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
(U)SIM peripheral circuit should be close to the (U)SIM card connector.
⚫
The pull-up resistor on USIM_DATA line can improve anti-jamming capability when long layout trace
and sensitive occasion are applied, and should be placed close to the (U)SIM card connector.
3.12. USB Interface
UG96 contains one integrated Universal Serial Bus (USB) interface which complies with the USB 2.0
specification and supports high speed (480Mbps) and full speed (12Mbps) modes. The USB interface is