HUAWEI MU736 HSPA+ M.2 Module
Hardware Guide
Description of the Application Interfaces
Issue 05 (2014-01-14)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
36
Figure 3-25
Circuit of the USIM card interface
The ESD protection component should choose low capacitance. The capacitance
of the component should
be
less than 10 pF.
To meet the requirements of 3GPP TS 51.010-1 protocols and electromagnetic
compatibility (EMC) authentication, the USIM socket should be placed near the
M.2 interface (it is recommended that the PCB circuit connects the M.2 interface
and the USIM socket does not exceed 100 mm), because a long circuit may lead to
wave distortion, thus affecting signal quality.
It is recommended that you wrap the area adjacent to the SIM_CLK and
SIM_DATA signal wires with ground. The Ground pin of the USIM socket and the
Ground pin of the USIM card must be well connected to the power Ground pin
supplying power to the MU736 module.
A 100 nF capacitor (0402 package is recommended so that larger capacitance
such as 1µF can be employed if necessary) and a 33 pF capacitor are placed
between the SIM_VCC and Ground pins in parallel. Three 33 pF capacitors are
placed between the SIM_DATA and Ground pins, the SIM_RST and Ground pins,
and the SIM_CLK and Ground pins in parallel to filter interference from RF signals.
It is recommended to take electrostatic discharge (ESD) protection measures near
the USIM card socket. Transient voltage suppressor diode should be placed as
close as possible to the USIM socket, and the Ground pin of the ESD protection
component is well connected to the power Ground pin that supplies power to the
MU736 module.
3.7 Tunable Antenna Control
The module provides 4 tunable antenna control pins.
