1

Transient Voltage Protection

By Curt Olsen

Director of Marketing & Sales, Scottsdale Division

Coordinating Activity for Transient Voltage Protection Products

2

The Circuit Protection Applications

Protection from:• Induced Lightning Spikes• Electrostatic Discharge (ESD)• Electrical Fast Transients (EFT)• Load Switching Spikes• NEMP Disturbances

3

Overview of the Damaging Effects• Lightning is the most obvious threat, heralding its presence with bright flashes across the sky and raucous thunder. Powerful

lightning strokes usually cause damage by inducing currents into both power and communication lines. Direct hits are rare. Specific information on threats are defined in IEC 1000-4-5, ANSI C62.41, FCC 195528 Part 68 and AIRINC DO-160C. These documents include both conducted and radiated threats. Worst case transients are more than 1 kA, with the low end of the spectrum at tens of amps. Occurring in multiple discharges, lightning typically has two to three strokes per flash but can range up to twenty for severe events. Although extensive data has been compiled to predict the flash density per square kilometer, lightning is predictably unpredictable, hence it is virtually impossible to know where the next strike will hit.

• Load switching is the silent killer, producing spikes (L(di/dt) effects) as described by Faraday’s laws of induction. Spike voltages can range from tens of volts to several thousand with associated short circuit currents from a few amps to greater than 200 A. Bursts can occur from resonance producing closely spaced, repetitive 2 kV spikes or “electrical fast transients” as defined in IEC 1000-4-4. Other documents defining induced transients are found in MIL-PRF-704, DOD-PRF-1399 and AIRINC DO-160C. Many laboratory and field observations support the conditions stated in these standards. The writer has observed 0.5 us, 1500 V closely spaced multiple voltage spikes while de-energizing relays. When your power fails, energy stored in inductive loads such as transformers and motors is dumped into the utility line. This produces spikes which can latch up controls on appliances.

• Electrostatic discharge (ESD) is the insidious killer that can zap a microchip with a spike of only 2 kV, well below the threshold of perception of the finger tip. Worst case values are 15 kV or more delivering 30 A. This threat is described in IEC 1000-4-2. The aspect of this threat which makes it so devastating is its fast rise time, in the subnanosecond range, with values reported as low as 100 picoseconds. Contacting and separating two dissimilar materials (leather shoe soles on wool carpeting or rubber sports shoes on tile) builds up an electric charge on both surfaces. The generation of static electricity is heavily influenced by ambient humidity. At 10% relative humidity, the amount of static build-up is about twice the level developed at 40%, and four

times the level at 55%.

4

Microsemi TVS Solutions

• Any package, any voltage, any power level

• All the “standard” solutions

– SMA/SMB/SMC/SML

– SOIC Arrays

– Axial

• plus:

– Low capacitance series

– Ultra low capacitance (USB)

– Low clamping voltage

– Multiple die stacks and arrays

– Miniaturization

– Any application specific solution

5

TVS Products - Market Size

33%

33%

12%

8%

5%4%

5%

GI/GSIMotorolaThomsonPhillipsTeccorMicrosemiOther

FY98 SAM=$665,000•Major competitors world wide

•GI/GSI 33%•Motorola 33%•Thomson 12%•Philips 8%•Teccor 5%•Microsemi 4%•Other 5%

•Market growth projected at 20%

6

TVS - Target Markets

• Aerospace - Chips, Cells, Hermetic Axial & SM

• Automotive - Chips & Wafers, Melf, Load-Dump

• Commercial - SM, Axial, Powermite, SOIC, USB, TSPD

• Computer - USB, SOIC, Powermite, SM, Axial

• Medical - Chips, Cells, Straps

• Industrial - Modules, SOIC, SM, Axial, Load-Dump

• Military - Metal Can, Modules, Hermetic Axial & SM

• Telecom - Powermite, SM, Axial, MSV (varistors), SMCLCE, TSPD

We have products for every market!

7

TVS-Product Portfolio• TVS Diodes

– Axial glass and plastic to 20kW– Surface mount glass and plastic to 3kW– Low cap and low voltage series

• TVSArrays– Standard and low capacitance– SO8 and SO16 packages

• USB TVSArray SO8– Ultra low capacitance– High frequency, low attenuation

• TVS Modules– Up to 1,000,000 watts per cubic inch– Any shape and terminal configuration

• TSPD “crowbar” Diodes– Plastic axial and surface mount– Standard products at 50A and 100A

8

TVS Diodes - Specifications

• Operating voltage: 3V thru 1000V

• Stacking and parallel configurations available

• Broad power rating: 150 watts thru 20kW

• Unipolar and bipolar configurations

• Low capacitance axial and surface mount

• Low clamping voltage series, axial and surface mount

• Packages:

– Axial glass and plastic

– Surface mount glass and plastic

– Powermite (soon Powermite 2)

– Chips, cells, Arrays

9

TVS Diodes - Thrust Products

• SMA 500 watt plastic surface mount• SMB 600 watt plastic surface mount• SMC 1500 watt plastic surface mount• SML 3000 watts in an SMC package• Powermite 150 watt miniature plastic SM• P3K3.0 low voltage series• SMCLCE low cap, 1500 watt TVS• Chips, Cells, Arrays, for hybrid applications• SMA, SMB Zener Diodes

10

TVS Diodes - Thrust Product Advantages

• SMA– Thermally superior to competition– Rated at 500 watts

• SML– Only one viable competitor– 3000 watts in a 15 watt package

• Powermite– Only one competitor– Smallest size TVS available

• SMCLCE– world’s only supplier

• Chips– Total wafer fab control– Time to market

Price competitive!

TVS Die for Hybrids

• Chips from .020 inch to .320 inch square• Unipolar or bipolar configurations• Disk-die-disk (cells) available

– 100% clamp tested– Any polarity uni- or bipolar– Any metallization top & bottom

• FlipChips for C.O.B. applications• Strap assemblies and arrays• Commercial or Hi-Rel (JANKC) available

12

TVS Diodes - New Products

• Powermite 2– 1500 watt TVS– Maintain PCMCIA height specification– Samples available in September

• P3K3.0-5.0– Low operating and clamping voltage (3-5 Volts)– Samples available now

13

SOIC TVSArraysTM

Capability•3.3V thru 36V+•Unipolar and Bipolar configurations•Low capacitance series•Any GI, Semtech, Protek socket•We Target SMDA and SMDB sockets•ESD protection (multi-line)•Commercial, Computer, Industrial markets

Thrust Products•USB 0805C•SMDA, SMDB•SMDAXXC-5•SMDAXXC-6•SMDAXXC-7

14

TVS Array Options

16

15

14

13

2

4

3

1

6

8

7

5

11

9

10

12

GND

N.C.

N.C.

5

2

4

3

1

16

15

14

13

2

4

3

1

6

8

7

5

11

9

10

12

16

15

14

13

2

4

3

1

6

8

7

5

11

9

10

12

16

15

14

13

2

4

3

1

6

8

7

5

11

9

10

12

15

USB08XX SOIC TVSArrays

• Capacitance of <5pF per line• Nanosecond response time• Low parasitic inductance• 300Watt peak pulse power @8/20uS• Leakage <50nA @ 3.5V• SO-8 surface mount package

Microsemi USB08 Series $1.40/10K pcsSemtech SL05-SL24(SOT-23) $0.50??Semtech LCDA or SRDA Series$1.50/10K pcsTI TUSV Series $1.00/10K pcs

Part Voltage DatasheetIDUSB0803C 3.3 Volts 24479USB0805C 5 Volts 24197USB0812C 12 Volts 24480USB0815C 15 Volts 24481USB0824C 24 Volts 24482

16

TVS Modules

• Power levels exceeding 1,000,000 watts per cubic inch• Focus on custom configurations• Unipolar or bipolar configurations• Low capacitance versions available• Second source all GSI modules• Microsemi is the primary supplier of lightning strike protection

modules to the commercial avionics industry.

17

TSPD DiodesSecondary lightning protection for:Communication and control lines•Central office systems•PABX’s•Subscriber station protectors•Related peripherals•Modems•Cable connectors

Unique Advantages:•Voltage triggered•Low on-state “crowbar” voltage•High current capability (up to 200A)•Positive slope V(BO)

•Minimize false triggering or partial turn-on

18

Target End Applications

• Computers/Peripherals– USB Applications– Modems– Printers

• Battery Chargers• IC Protection• Lightning Protection• Mil/Aero Solutions

19

Selecting a TVS Diode

• What peak surge power is required (watts vs time)• Stand off voltage equal to or greater than the normal

circuit operating voltage• Clamping voltage below the voltage that could cause

damage to the protected component• Unipolar or bipolar configurations

• Microsemi has over 12,000 TVS device types

• You can find the part you need by using our selection guide tools or by using the TVS Cross Reference Guide.

20

• Over 60% of the field failures of High Speed CMOS devices such as those used in the USB are destroyed by ESD

• Most of these devices (almost 90%) are destroyed at ESD levels of less than 2KV

• 3KV can easily pass through your finger without notice

Universal Serial Bus

21

Battery Chargers

• Forward AC/DC Converter-charger (Sample Circuit)– Cellular Phones– Laptops/Notebooks

LOAD

600WTVS

1Amp, 20V or 40VSCHOTTKY

SYNC

22

IC Protection• ESD is the threat• Our solutions:

– SMA/SMB/SMC/SML– Powermite TVS– Powermite Zeners– SOIC Arrays– Flip Chips– Cells– MELF TVS– Standard Zener Diodes

• We offer selective versions of:– SOT23– SOD123

23

Lightning Protection

• Conducted Threats• Radiated Threats

• Solutions:– TSPD “Crowbar” Diodes– Modules– Clamping Diodes

24

Mil/Aero Solutions

• JANTX/TXV 1500 Watt Metal Axial• Modules

– JANTX/TXV Subassemblies– JANTX/TXV Equivalent Screening

on Module– Both

• Chips and cells for hybrid applications

• Complete line of military and space level products available from both Santa Ana and Scottsdale.

25

Application Summary

• Any place a design needs to protect from a Transient Voltage or Current Spike…we have the products.

• Any place where space/size is critical.• Any place where “the big guys” have left them hanging…

Microsemi has the infrastructure to respond quickly.• Diversity, diversity, diversity…we have products for all

applications - from heart pacers to laptops.

26

Zener Diodes

New Products for FY98•Powermite Zeners•BZY93

–DO4–10 Watt Stud

•BZY91–DO5–100 Watt stud

New Products •SMAJ4728-4764A 2 Watt, SMAJ•SMAJ5913-5956B 3 Watt, SMAJ•SMBJ5333-5388B 5 Watt, SMBJ•10EZ 3,9-100B 10 Watt, TO-220•MMBZ5226-5261B SOT23•BZX84C3V3-C47 SOT23

27

New Brochure

A new brochure outlining or TVS capabilities is now available.

A complimentary website to the new brochure exists at:

http://www.microsemi.com/TVS/

28

TVS FAQs• Are there application notes for TVS?

101 A primer on transient voltage102 An introduction to transient voltage suppressor devices103 What is a silicon transient voltage suppressor104 Using the power vs time curve105 What is a thyristor surge protector device106 Crowbars and clamps107 Cross referencing TVS devices108 Determining a range of clamping voltages for a range of pulse currents109 Protecting from electrostatic discharge110 Parasitic capacitance in transient voltage suppressors111 Parasitic lead inductance on transient voltage112 Series stacking of silicon TVSs for higher surge current113 Parallel stacking of silicon TVSs for higher surge current114 Derating of silicon TVSs for higher junction temperatures115 Derating transient voltage suppressors at elevated temperatures for

varying pulse widths116 Protection at a transformer117 Protecting USB data I/O ports118 TVS/Chip product overview