MS2131
Hardware Design Guide
MS2131 ESD Design Guide
Issue 02 (2017-1-13)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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9
MS2131 ESD Design Guide
9.1 PCB Design Recommendations for the Host
1.
A four-layer or six-layer PCB is recommended. Two-layer PCBs are not recommended.
2.
Use a large-capacity ceramic bypass capacitor and decoupling capacitor on the MS2131
power supply. Place the capacitors within 30 mils from the connector. The PCB cable
routing width must be at least 20 mils. Deploy dedicated power cable plane and ground
or tight power and ground grid. Use a transient voltage suppressor (TVS) for external
electrical overstress (EOS) protection. It is recommended that a component that has a
peak power larger than 100 W at 8/20 µs be used.
3.
If the signal cable length is larger than 300 mm (12 inches), surround the sides of the
signal cables by grounds. Drill holes on the grounds to connect them to the main ground.
4.
When connecting the host to the MS2131, ensure the grounding reliability.
5.
Use TVSs at the joint between the MS2131 and the host. The TVS on the male connector
must have a parasitic capacitance less than 1 pF while the TVS on the power supply must
have a peak power larger than 100 W at 8/20 μs
9.2 Shell Design Recommendations for the Host
The MS2131 comes with ESD protection. The SIM card and connector have high
requirements for ESD protection.
To prevent users from directly touching the SIM card area, cover the area with a mechanical
part.