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HUAWEI EM820W HSPA+ PC Embedded Module
Hardware Guide
Table 3-8 SIM IO requirements
IO
V
IL
V
IH
V
OL
V
OH
3.6.3 Certification Test
Using test equipment simulates a (U)SIM card to test U(SIM) protocol in GCF or
PTCRB test, If some test. If you encounter some issues during SIM/USIM test,
please contact Huawei for more details.
Issue 01 (2010-12-09)
The V
max of 0.45 V for the output is specified at an output current of 3 mA whereas the
OL
V
max of 0.4 V for the SIM IO input is specified at an input current of 1 mA. With the smaller
IL
current drive, the output voltage would be driven lower than the stated maximum value.
ESD protection
Since the SIM is a CMOS device, ESD protection devices should be placed near
the SIM connector to provide protection before connecting to the module. In
addition, all the SIM interface signals should be bypassed with a 10 pF capacitor.
The used ESD device (PESD3V3L5UY, NXP) in Figure 3-2 is a low capacitance
5-fold ESD protection diode arrays in SOT363 package.
Clock frequency
The SIM must support clock frequencies between 1 MHz and 4 MHz. (The Mini
Card can be programmed to generate a clock of 1.625 MHz, 2.6 MHz, or 3.25
MHz.)
Routing recommendations
The SIM interface signals consist of four signals that are UIM_PWR, UIM_RST,
UIM_CLK, and UIM_DATA (UIM_Vpp is neither connected nor used in many
applications). Due to the relatively low clock frequencies involved, the concern is
not the degradation of the SIM signals but that of routing of the SIM interface
signals through areas considered to be of high risk for RF noise coupling
(crosstalk and RF contamination), which can desensitize the radio circuitry. The
general guidelines that should be followed are listed as follows:
It is recommended that these signals should be routed over a continuous
−
ground plane.
SIM interface signals should not be routed near high transient signals (power
−
supply chokes and DC/DC switching FETs).
Prevent routing of these signals near output connectors.
−
Keep SIM interface signals isolated from other signals. 2x width spacing (1.5x
−
min) between SIM interface signals and all other signal routing is
recommended.
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
Description of the Application Interfaces
Minimum
0
0.7Vcc
–0.3
0.7 Vcc
Maximum
0.4
Vcc
0.2 Vcc
Vcc+0.3
13
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