UMTS/HSPA+ Module Series
UG89 Hardware Design
UG89_Hardware_Design 36 / 73
Module
USIM_VDD
USIM_GND
USIM_RST
USIM_CLK
USIM_DATA
USIM_DET
0R
0R
0R
VDD_EXT
51K
100nF
GND
GND
33pF
33pF 33pF
VCC
RST
CLK
IO
VPP
GND
GND
USIM_VDD
15K
(U)SIM Card Connector
Figure 15: Reference Circuit of (U)SIM Interface with an 8-pin (U)SIM Card Connector
If (U)SIM card detection function is not needed, please keep USIM_DET unconnected. A reference circuit
for (U)SIM interface with a 6-pin (U)SIM card connector is illustrated in the following figure.
Module
USIM_VDD
USIM_GND
USIM_RST
USIM_CLK
USIM_DATA
0R
0R
0R
100nF
GND
33pF
33pF 33pF
VCC
RST
CLK
IO
VPP
GND
GND
15K
USIM_VDD
(U)SIM Card Connector
Figure 16: 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
customers’ 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
less than 200mm as far as possible.
Keep (U)SIM card signals 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 and USIM_VDD no less than 0.5mm to maintain the same electric potential. If the
ground is complete
on customers’ PCB, USIM_GND can be connected to PCB ground directly.
To avoid cross-talk between USIM_DATA and USIM_CLK, keep them away from each other and shield
them with the surrounded ground.