Emc And Esd Features - Huawei MU709 Series Hardware Manual

HUAWEI MU709 Series HSPA+ LGA Module
Hardware Guide

5.6 EMC and ESD Features

The following are the EMC design comments:
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The following are the requirements of ESD environment control:
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Issue 09 (2017-12-15)
Attention should be paid to static control in the manufacture, assembly, packaging,
handling and storage process to reduce electrostatic damage to HUAWEI
module.
RSE (Radiated Spurious Emission) may exceed the limit defined by EN301489 if
the antenna port is protected by TVS (Transient Voltage Suppressor), which is
resolved by making some adjustment on RF match circuit.
TVS should be added on the USB port for ESD protection, and the parasitic
capacitance of TVS on D+/D- signal should be less than 2 pF. Common-mode
inductor should be added in parallel on D+/D- signal.
TVS should be added on the USIM interface for ESD protection. The parasitic
capacitance of TVS on USIM signal should be less than 10 pF;
Resistors in parallel and a 10nF capacitance should be added on RESIN_N and
POWER_ON_OFF signal to avoid shaking, and the distance between the
capacitor and the related pins should be less than 100 mil.
A TVS should be added to the module power supply. It is recommended that the
TVS's Clamping Voltage (V
at least 100 W.
PCB routing should be V-type rather than T-type for TVS (Transient Voltage
Suppressor).
An integrated ground plane is necessary for EMC design.
The electrostatic discharge protected area (EPA) must have an ESD floor whose
surface resistance and system resistance are greater than 1 x 10
Ω.
9
than 1 x 10
The EPA must have a sound ground system without loose ground wires, and the
ground resistance must be less than 4 Ω.
The workbench for handling ESD sensitive components must be equipped with
common ground points, the wrist strap jack, and ESD pad. The resistance
between the jack and common ground point must be less than 4 Ω. The surface
resistance and system resistance of the ESD pad must be less than 1 x 10
The EPA must use the ESD two-circuit wrist strap, and the wrist strap must be
connected to the dedicated jack. The crocodile clip must not be connected to the
ground.
The ESD sensitive components, the processing equipment, test equipment, tools,
and devices must be connected to the ground properly. The indexes are as
follows:
Hard ground resistance < 4 Ω
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Ω ≤ Soft ground resistance < 1 x 10
5
1 x 10
−
Ω ≤ ICT fixture soft ground resistance < 1 x 10
5
1 x 10
−
The electronic screwdriver and electronic soldering iron can be easily oxidized.
−
Their ground resistance must be less than 20 Ω.
The parts of the equipment, devices, and tools that touch the ESD sensitive
components and moving parts that are close to the ESD sensitive components
must be made of ESD materials and have sound ground connection. The parts
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Electrical and Reliability Features
) be smaller than 12 V and Peak Pulse Power (P
CL
Ω
9
PP
Ω while less
4
Ω.
9
Ω
11
63
)