Avalanche Diode - hay Jay b

8/2/2019 Avalanche Diode - hay Jay b.

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Avalanche Diode


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WhatisAvalancheDiode

Adiodethatisdesignedtogothroughavalanchebreakdownataspecifiedreversebiasvoltage

Thisdiodeconductsinreversebiasconditionwhere

thereversebiasvoltageappliedacrossthep-njunctioncreatesawaveofionizationleadingtotheflowoflargecurrent.

Thesediodesaredesignedtobreakdownatspecificreversevoltageinordertoavoidanydamage.


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AvalancheBreakdown

Aformofelectriccurrentmultiplicationthatcanallowverylargecurrentswithinmaterialswhichareotherwisegoodinsulators

Theavalanchebreakdownisduetominoritycarriersacceleratedenoughtocreateionizationinthecrystallattice,producingmorecarrierswhichinturncreatemoreionization.

Becausetheavalanchebreakdownisuniformacrossthewholejunction,thebreakdownvoltageismorenearlyconstantwithchangingcurrentcomparedtoanon-avalanchediode.


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AvalancheDiodeVSZenerDiode

Avalanche diode

Optimizedforavalancheeffectsotheyexhibitsmallbutsignificantvoltagedropunderbreakdownconditions

haveasmallpositivetemperaturecoefficientofvoltage

Zener Diode keepvoltagealwayshigherthanbreakdown

haveanegativetemperaturecoefficient


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Applications/Uses

VoltageReference

Protection

RFNoiseGeneration

MicrowaveFrequencyGeneration

SinglePhotonAvalancheDetector


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Voltage Reference

The voltage after breakdown varies only slightly withchanging current. This makes the avalanche diodeuseful as a type of voltage reference. Voltagereference diodes rated more than about 5.5 volts areavalanche diodes

A common application is protecting electroniccircuits against damaging high voltages. The avalanchediode is connected to the circuit so that it is reverse-

biased If the voltage increases beyond the design limit, the

diode goes into avalanche breakdown, causing theharmful voltage to be conducted to ground

They are often referred to as clampingdiodes or transient voltage suppressors because they"clamp" the maximum voltage to a predetermined

level.

Protection


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RF Noise Generation

Avalanche diodes generate radio frequency noise. Commonly used as noise sources in radio equipment

and hardware random number generators

If placed into a resonant circuit, avalanche diodes can

act as negative resistance devices. The IMPATT diode is an avalanche diode optimized for

frequency generation.

Microwave FrequencyGeneration


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Single Photon AvalancheDetector

The silicon avalanche photodiode is a high gain photon

detector. These are made from doped silicon and depend on the

avalanche breakdown effect to detect even singlephotons.


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References

http://en.wikipedia.org/wiki/Avalanche_diode

http://www.engineersgarage.com/tutorials/diodes?page=3

http://www.buzzle.com/articles/types-of-diodes.html
http://en.wikipedia.org/wiki/Avalanche_diodehttp://www.engineersgarage.com/tutorials/diodes?page=3http://www.buzzle.com/articles/types-of-diodes.htmlhttp://www.buzzle.com/articles/types-of-diodes.htmlhttp://www.buzzle.com/articles/types-of-diodes.htmlhttp://www.buzzle.com/articles/types-of-diodes.htmlhttp://www.buzzle.com/articles/types-of-diodes.htmlhttp://www.buzzle.com/articles/types-of-diodes.htmlhttp://www.engineersgarage.com/tutorials/diodes?page=3http://en.wikipedia.org/wiki/Avalanche_diode

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Avalanche Diode - hay Jay b