9.esd suppression

7/29/2019 9.ESD Suppression

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ESD Suppression


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http://www.roc-noc.com/product.php?productid=286&cat=31&page=1


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Introduction/Circuit Protection

Voltage Transients - Emphasis on ESD ESD Suppression Technologies

Usage of ESD Suppressors - In Applications

Board Layout Considerations

Overview:


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OVERCURRENT

PROTECTION

OVERVOLTAGE

PROTECTION

CIRCUIT PROTECTION

Circuit Protection Overview


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ESD

Suppressor

Fuse/PTC CircuitryPower

Source

PowerInput

Fuses/PTCsSeries devices that open

to break overload currents.

Digital Waveform

Littelfuse ESD SuppressorsParallel devices that shunt

damaging transients to ground.

Fault Current

Signal

Input

ESD

Pulse

Circuit Protection Comparison


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A sudden change in the electrical condition of any circuit

will cause a transient voltage to be generated from the

energy stored in circuit capacitance and inductance.

Effective transient overvoltage protection requires that the

impulse energy be dissipated in the added suppressor at a

voltage low enough to ensure survival of the circuit

components.

What is an Electrical Transient?


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ESD (Electro-Static Discharge)

Lightning Strike

Inductive Load Switching

Commutative Spikes

Automotive Load Dump

Examples of Voltage Transients


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75% of field equipment failure are caused by Electrical

Over-Stress (EOS)!!!

Semiconductor devices are becoming increasingly

Intolerant to voltage transients

ALightningstrike several miles away can induce

transients in your equipment

Power distribution transformers susceptibility impacts

clean power condition

ESD failures can occur in CMOS at 2kV common,

where as most EOS occurrences are at 8kV or higher

Did You Know?.


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EMC REQUIREMENTS

ESD

EFT SURGES

WHITE GOODS

LINE TRANSFORMER

PROTECTION

LIGHTNING INDUSTRIAL

PANELS

TVSS APPLICATIONS

UL 1449, BSS 587

ANSI C62.1

PORTABLE ELECTRONIC

EQUIPMENT

ESD

TELECOM

EQUIPMENT

AUTOMOTIVE

ISO 7637

GM 9105

LOAD DUMP

PROTECTION OF

INDUCTIVE LOADS

TRANSIENT BURSTS

Suppression

Where is Transient Protection Needed?


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DEFINITION: The rapid transfer of

electrostatic charge between objects.

Discharges below 3,000V are usually not

perceived by humans Discharges can exceed 15,000V

Not lethal to humans, but can damage or kill

electronic devices during production or in the

field

ESD exists EVERYWHERE

What is ESD (ElectroStatic Discharge)?


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The human body is a good generator of ESD

The potential between a human body & an object canexceed 35,000 volts.


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Typical ESD values

Means of Static Generation ESD @ 10 20%Relative Humidity

ESD @ 65 90%Relative Humidity

Walking across carpet 35,000 V 1,500 V

Walking over vinyl floor 12,000 V 250 V

Worker at bench 6,000 V 100 V

Vinyl envelope 7,000 V 600 V

Work chair padded withpolyurethane 18,000 V 1,500 V


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DEVICES ARE GETTING MORE SENSITIVE:

SMALLER FEATURES, DENSER IC GEOMETRIES

Lower Operating Voltages

Higher Operating Speeds

Greater Functionality

ESD ACCOUNTS FOR 30% OF ALL FIELD

FAILURES

DEMANDING NEW STANDARDS

LIMITATIONS OF EXISTING DEVICES

The Need for ESD

Protection is Increasing


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Vline

Transient Event

Crowbar Suppression Device:

e.g Surgector

Vline

Trigger Voltage

Reset Time

Crowbar Devices


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Multi Layer Varistor (MLV)

Designed for Low-Voltage DC Applications;

3.5V to 120V

Applications can include:

ML and MLE Series: Low Voltage, Board Level

Products (Hand-Held/Portable devices, Computer/EDP,

Instrumentation, Medical Electronics, etc.)

AUML and ML Series: Automotive Electronics

(Antilock brake systems, Wiper Modules, Airbag control

systems, etc.)

ML and MLE Series: Telecommunications Products(Cellular/Cordless Phones, Modems, Line Cards, etc.)


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SurgeArray Multi layer Varis to r

Network The SurgeArray network is a set offour independent Multilayer Varistors in a

single surface mount package (1206).

SurgeArray Networks were designed to meet the needs ofthe Battery Operated, Portable / Handheld, Automotive, andIndustrial Markets.

The SurgeArray network helps your customers meetmandatory EMC requirements by suppressing ESD, EFT andother potentially damaging transients either generated orexperienced by their systems.

The inherent capacitance of Littelfuses Multilayer VaristorTechnology provides filtering capability to eliminate the needfor an additional capacitors.

SurgeArray networks increase component density, thusreducing board space, assembly placement costs, partscount, and system reliability

Direct upgrade for AVX(Multiguard) and Epcos (CA06 series).

=

4 0603s = 1 SurgeArray

MLV Networknot to scale


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The SP72X..A Family of Silicon Bipolar Diode / SCRIC Arrays Designed for Suppression of ESD and Other

Transients !

SP Series Diode/SCR Arrays


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Connect Input (IN) to SensitiveLine Needing Protection

Lower Pair: Clamps at 0.7Vbelow V-


Upper Pair: Clamps at 0.7Vabove V+


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Applications can Include:

Data Lines ( Parallel Ports, I/O lines, High Speed

Logic, Serial lines / USB, Switches )

Signal Lines ( Op Amps, Sensors, Comparators,

A-D lines, Receiver / Transceivers ) Control Lines ( Motor, Alarms, Pumps, Robotics )

Discrete Component Input ( MOSFET, Drivers )



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Surface Mount Avalanche

Diode Arrays

Family of avalanche diode arrays designed and testedspecifically for Transient Voltage Suppression (TVS) andEMC requirements.

Targeting applications with working voltages of 5 volts andbelow, including 3.3V systems.

Configured to protect 2, 3, 4, 5 and 6 data or signal lines inultra small SOT-23, TSSOP and MSOP packages

NAFTA represents 45% of world Avalanche Diode marketmaking this a great play for North American Distribution

Littelfuse TVS diode expansion continues with Chip Scale

Packaging in June, and more Rail Clamps in July The new Avalanche family enhances our portfolio of the

widest selection of TVS and ESD Technologies in the knownGalaxy.

Avalanche Diode Market Size

NAFTA45%

Asia28%

$350M

Europe27%

Total World WideAvalanche Diode

Avalanche DiodeSAM

$120M


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Substrate

Copper

Plating

Nickel

Plating

Tin

Plating

The Gap

Voltage Variable Material

Coating

PulseGuardVVM ESD Suppressors

Lowest Capacitance (0.050pF)

Uses polymer voltage variablematerial (VVM) instead of

electroceramic of MLVs

Supplements the on-board TVS

protection of ICs and ASICs


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Cu/Ni Electrode

Polymer binder

Cu/Ni Electrode

Metallic particleSemiconductor particle

Controlling PulseGuard1) Change VVM formula

2) +/- width of electrodes

3) +/- width of gap

Voltage Variable Material

Polymer binder

+ Metallic particles

+ Semiconductor particles

Electrode

Width

The Gap



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Benefit

Compatible with pick-and-place

technologies, and reflow and wave

solder processes.

< 1pF (0.055 pF); PulseGuard does

not interfere with high speed signals.

< 100 pA; PulseGuard pulls virtually

no current from battery in portable

applications, does not interfere with

high input impedance circuits.

Minimizes new product lead-time.

Custom products can be turned

around quickly.

Feature

Surface Mountable

Low Capacitance

Low Leakage Current

Configurability



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Computer

Desktop Laptops/Notebooks

Peripherals (Monitor/Display, Printer, Scanner, Plotter)

Network Hardware

Electronic

Personal Digital Assistants (PDAs) Flat Panel Displays

Digital Set Top Boxes

Industrial/Process Controllers

Multimedia Interface Hardware

Medical and Test Equipment

Telecom Cell Phone Data Ports

Secondary side of Network Interface Products

Target App l icat ions


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Target Appl icat ions

ESD Protection for signal, data and control linesCellular Phones

PDAs

Digital Cameras

Printers

Set-top boxes

Cable ModemDSL Modem

Laptop Computers

Cable Modem

Cell Phone

PDA

Digital Camera


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STRAY CAPACITANCE CONSIDERATION

.... Goal is to minimize/eliminate signal distortion

Time

Voltage

Desired Digital Wave Shape

Distorted Wave Shape

LOW LEAKAGE CURRENT

. Compatible with low-power portable equipment

and High-Impedance analog circuits

Key Characteristics of ESD Suppressors


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Capacitance Key:

V5.5MLA0603 - 660 pFSMD Capacitor - 390 pF

V18MLE0603 - 100 pF

PGB0010603 - 0.05 pF


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FAST RESPONSE TIME

LOW CLAMPING VOLTAGE

HIGH CURRENT HANDLING

.... These features give the suppressor the ability to protect

sensitive components against multiple severe ESD events

TVS

IC with Internal TVS Structures

Rs

SMALL SIZE -- There are no Diodes or MOVs that can provide low capacitance in the 0603 size!!

LF

ESD

Key Characteristics of ESD Suppressors


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ESD Suppressor Usage - General Overview

Integrated Circuitry

(To be protected)

Data/Signal Interface

Human/User Interface

AC/DC

Power

Input

USB, FireWire, DSub, RJ (Ethernet), Antenna, etc

Keyboard, Keypad, Speaker, Mouse, etcExamples

Computer (networks, peripherals)

Flat Panel DisplaysPersonal Digital Assistants (PDAs)

Cell phones, pagers

Set top boxes (satellite and cable)

Medical Equipment

Test Instrumentation

The speed of the signals found on theinterface (I/O) lines will help determine

which ESD technology to use.

- MultiLayer Varistors, SCR/Diodes, PulseGuard

ESD Suppressor(s)


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D+

D-

VBUS

Signal

Ground

USB

Port USBController

OutsideW

orld

PGB0010603

Note: ESD suppressor must be installed as close

to the connector as possible to minimize overshoot

D+

D-

VBUS

Signal

Ground

Via to

VBUS

Plane

PGB0010603

PTC - 1812L260

MLV - V5.5MLA0603

MLV - V5.5MLA0603

Via to

Signal Ground

Plane

Via to

Signal Ground

Plane

Application Example - USB2.0 BusUSB2.0, up to 480 Mbps

Signal

GroundShield/Chassis

Ground


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USB

Ports

OutsideWor

ld

USB

Controller

1D+

1D -

VBUS

Ground

1812L150

1 2

6

3

5 4 SP0505BAHT

2D+

2D -

USB

Port 1

USB

Port 2

Dual Port Universal Serial Bus (USB)

SMT Avalanche Diode App l icat ion Examples


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D+(1)

D-(1)

VBUS

Signal

Ground

1394b

Port 1394bController

OutsideWorld

PGB0010603

Note: ESD suppressor must be installed as close

to the connector as possible to minimize overshoot

PGB0010603

D-(2)

D+(2)PGB0010603

PGB0010603

PTC - 1.5A, 33V

MLV - V33MLA1206

Application Example - IEEE 1394b Bus1394b, up to 1.6 Gbps

Signal

GroundShield/Chassis

Ground


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Antenna

- 800 - 1800 MHz

- PGB0010603

Keypad- low speed

- V9MLA0603

- V18MLN41206

I/O Connector

- medium to high speed

- V9MLA0603- V18MLN41206

- PGB0010603

- PGB008CA10

Cell Phone Application Example


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Minimize Distance Between the ESD Event

and the ESD Suppressor

Maximize Distance Between the ESD

Suppressor and the I/C to be Protected

Minimize Impedance between the ESD

Suppressor and Ground

Board Layout Considerations


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Keep the trace lengths from the I/O line to

the Suppressor and from the Suppressor to

the Ground plane as short as possible

Minimize bends in board traces

Minimize Suppressor-Ground Impedance


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TVS

D1 D2

Due to fast rise time of ESD transient,

lengths (trace and lead) becomeextremely important. They will affect

the voltage that is ultimately seen by

the IC to be protected.

Two Key Design Parameters

Issue Solution

TVS to use Surface Mount; close to I/O line (D3 is small)

Placement of TVS Minimize distance to source (D1 is small)

I/O Line

D3

Signal

Ground

Minimize Suppressor-Ground Impedance

9.esd suppression

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