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Basic DefinitionsDocument Number 84067 www.vishay.com

Basic Sinterglass Diode ParametersThe major parameters for the selection of the appro-priate sinterglass diodes are the maximum reversevoltage (VRRM), the average forward current (IFAV)and for switching application the reverse recovery

characteristic (trr), too. Additional parameters may befor example the reverse avalanche energy capability(ER) and forward surge capability (IFSM) etc.

VR Reverse voltageVRRM Repetitive peak reverse voltage, including all repeated reverse transient voltagesV(BR)R Reverse breakdown voltageIR Reverse (leakage) current, at a specified reverse voltage VR and temperature TJIF Forward current VF Forward voltage drop, at a specified forward current IF and temperature TJIFAV Average forward output current, at a specified current waveform (normally 10ms/50Hz half-sine-

wave, sometimes 8.3ms/60Hz half-sine-wave), a specified reverse voltage and a specified mounting condition (e.g. lead-length = 10mm or PCB mounted with certain pads and distance)

IFSM Peak forward surge current, with a specified current waveform (normally 10ms/50Hz half-sine-wave, sometimes 8.3ms/60Hz half-sine-wave),

trr Reverse recovery time, at a specified forward current (normally 0.5A), a specified reverse current (normally 1.0A) and specified measurement conditions (normally from 0 to 0.25A)

ER Reverse avalanche energy, non-repetitive

Polarity ConventionsThe voltage direction is given by an arrow which points from the measuring point

to the reference pointor

by a two letter subscript, where the first letter is the measuring point and the second letter is the refer-ence point.

The numerical value of the voltage is positive if thepotential at the arrow tail is higher than at the arrowhead; i.e., the potential difference from the measuringpoint (A) to the reference point (B) is positive.The numerical value of the voltage is negative if thepotential at the arrow head is higher than the tail; i.e.,the potential difference from the measuring point tothe reference point is negative.

In the case of alternating voltages, once the voltagedirection is selected it is maintained throughout. Thealternating character of the quantity is given with thetime dependent change in sign of its numerical values.

The numerical value of the current is positive if thecharge of the carriers moving in the direction of thearrow is positive (conventional current direction), or ifthe charge of the carriers moving against this direc-tion is negative. The numerical value of the current isnegative if the charge of the carriers moving in thedirection of the arrow is negative, or if the charge ofthe carriers moving against this direction is positive.The general rules stated above are also valid for alter-nating quantities. Once the direction is selected, it ismaintained throughout. The alternating character ofthe quantity is given with the time-dependent changein sign of its numerical values.

Figure 1.

A

B

V1

A

B

A

B

VAB V2=V1=VBA=VAB

94 9315

Figure 2.

A B A BI1 I2 = I1

94 9316Rev. 7, 07-Jan-03 1

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Polarity conventions for diodes CAPITAL letters are used as subscripts for the desig-www.vishay.com Document Number 84067

Here, the direction of arrows is selected in such a waythat the numerical values of currents and voltages arepositive both for forward (F or f) and reverse (R or r)directions.

Arrangement of SymbolsLetter symbols for current, voltage and power (according to DIN 41 785, sheet 1)To represent current, voltage and power, a system ofbasic letter symbols is used. Capital letters are usedfor the representation of peak, mean, DC or root-mean-square values. Lower case letters are used forthe representation of instantaneous values whichvary with time.Capital letters are used as subscripts to representcontinuous or total values, while lower case letters areused to represent varying values.The following table summarizes the rules given above.

Letter symbols for impedance, admittances, two-port parameters etc.For impedance, admittance, two-port parameters,etc. capital letters are used for the representation ofexternal circuits of which the device is only a part.Lower case letters are used for the representation ofelectrical parameters inherent in the device.

nation of static (DC) values, while lower case lettersare used for the designation of small-signal values.If more than one subscript is used (hFE, hfe), the lettersymbols are either all capital or all lower case.If the subscript has numeric (single, double, etc.) aswell as letter symbol(s) (such as h21E or h21e'), the dif-ferentiation between static and small-signal value ismade only by a subscript letter symbol.Other quantities (values) which deviate from theabove rules are given in the list of letter symbols.The following table summarizes the rules given above.

Examples:GP Power gainZS Source impedancefT Transition frequencyIF Forward currentExample for the use of symbolsaccording to 41785 and IEC 148

VF Forward voltageVR Reverse voltageVFSM Surge forward voltage (non-repetitive)

Figure 3.

Basic letterUpper-case Upper-case

Instantaneous values which vary with time

Maximum (peak) average (mean) continuous (DC) or root-mean-square (RMS) values

Subscript(s)Upper-case Upper-case

Varying component alone, i.e., instantaneous,root-mean-square, maximum or average values

Continuous (without signal) or total (instantaneous, average or maximum) values

A IF K

A IR K

VF

VRBasic letter

Upper-case Upper-caseElectrical parameters inherent in the semiconductor devices except inductances and capacitances

Electrical parameters of external circuits and of circuits in which the semiconductor device forms only a part; all inductances and capacitances

Subscript(s)Upper-case Upper-case

Small-signal values Static (dc) values

Figure 4.

VFWM

VFSM

t

VF

VRSM

VRRMVRWM

VR

0

93 7796

VFRM2 Rev. 7, 07-Jan-03

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VRSM Surge reverse voltage (non-repetitive) Ptot Total power dissipationDocument Number 84067 www.vishay.com

VFRM Repetitive peak forward voltageVRRM Repetitive peak reverse voltageVFWM Crest working forward voltageVRWM Crest working reverse voltage

List of SymbolsA Anodea Distance (in mm)bpn Normalized power factorC Capacitance, generalCcase Case capacitanceCD Diode capacitanceCi Junction capacitanceCL Load capacitanceCP Parallel capacitanceER Reverse avalanche energy, non-repetitiveF Noise figuref Frequencyfg Cut-off-frequencyg ConductanceK Kelvin, absolute temperatureIF Forward currentiF Forward current, instantaneous total valueIFAV Average forward current, rectified currentIFRM Repetitive peak forward currentIFSM Surge forward current, non-repetitiveIFWM Crest working forward currentIR Reverse currentIRM Maximum reverse currentiR Reverse current, instantaneous total valueIRAV Average reverse currentIRRM Repetitive peak reverse currentIRSM Non-repetitive peak reverse currentIRWM Crest working reverse currentIS Supply currentIZ Z-operating currentIZM Z-maximum currentl Length (in mm), (case-holder/soldering point)LOCEP (local epitaxy)

A registrated trade mark of TEMIC for a pro-cess of epitaxial deposition on silicon. Applica-tions occur in planer Z-diodes. It has an advantage compared to the normal process, with improved reverse current.

P PowerPR Reverse Power

PV Power dissipation, generalPvp Pulse-power dissipationQ QualityQrr Reverse recovery chargeRF Forward resistancerf Differential forward resistanceRL Load resistorrP Parallel resistance, damping resistanceRR Reverse resistancerr Differential reverse resistancers Series resistanceRthJA Thermal resistance between junction and

ambientRthJC Thermal resistance between junction and caseRthJL Thermal resistance junction leadrz Differential Z-resistance in breakdown region

(range) rz = rzj + rzthrzj Z-resistance at constant junction temperature,

inherent Z-resistancerzth Thermal part of the Z-resistanceT Temperature, measured in centigradeT Absolute temperature, Kelvin temperatureT Period durationTamb Ambient temperature (range)tav Integration timeTcase Case temperaturetfr Forward recovery timeTj Junction temperatureTK Temperature coefficientTL Connecting lead temperature in the holder (sol-

dering point) at the distance/(mm) from casetP Pulse duration (time)

Duty cycle

tr Rise timetrr Reverse recovery timets Storage timeTsd Soldering temperatureTstg Storage temperature (range)V(BR) Breakdown voltageVF Forward voltageVF Forward voltage, instantaneous total valueVFAV Average forward voltageVo Rectified voltageVFP Turn on transient peak voltage

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VFSM Surge forward voltage, non-repetitive VRWM Crest working reverse voltagewww.vishay.com Document Number 84067

VFRM Repetitive peak forward voltageVFWM Crest working forward voltageVHF RF voltage, RMS valueVHF RF voltage, peak valueVR Reverse voltageVR Reverse voltage, instantaneous total valueVRSM Surge reverse voltage, non-repetitiveVRRM Repetitive peak reverse voltage

VS Supply voltageVT Temperature voltageVZ Z-operating voltageZthp Thermal resistance - pulse operation Angle of current flowr Rectification efficiencyTo Time constantCD Capacitance deviation

Data Sheet ConstructionData sheet information is generally presented in thefollowing sequence: Device description Absolute maximum ratings Thermal data - thermal resistances Characteristics, switching characteristics Electrical characteristics Dimensions (mechanical data)Additional information on device performance is pro-vided where necessary.Device DescriptionThe following information is provided: part number,semiconductor materials used, sequence of zones,technology used, device type and, if necessary con-struction.Also, information on the typical Applications and spe-cial Features is givenAbsolute Maximum RatingsThe absolute maximum ratings indicate the maximumpermissible operational and environmental condi-tions. Exceeding any one of these conditions couldresult in the destruction of the device. Unless other-wise specified, an ambient temperature of 25C 3C is assumed for all absolute maximum ratings.Most absolute ratings are static characteristics; if theyare measured by a pulse method, the associatedmeasurement conditions are stated.Maximum ratings are absolute (i.e., not interdependent).Any equipment incorporating semiconductor devicesmust be designed so that even under the most unfa-vorable operating conditions the specified maximumratings of the devices used are never exceeded.These ratings could be exceeded because ofchanges in: Supply voltage

The properties of other components used in the equipment

Control settings Load conditions Drive level Environmental conditions The properties of the devices themselves (aging)Thermal Data - Thermal ResistancesSome thermal data (e.g., junction temperature, stor-age temperature range, total power dissipation),impose a limit on the application range of the device,and are given under the heading "Absolute MaximumRatings".A special section is provided for thermal resistances.Temperature coefficients, on the other hand, arelisted together with the associated parameters underCharacteristics, Switching Characteristics.Characteristics, Switching CharacteristicsUnder this heading, the most important operationalelectrical characteristics (minimum, typical and maxi-mum values) are grouped together with associatedtest conditions supplemented with graphs.Dimensions (Mechanical Data)Important dimensions and the sequence of connec-tions supplemented by a circuit diagram are includedin the mechanical data. Case outline drawings carryDIN, JEDEC or commercial designations. Informationon weight complete is also included.Note:If the dimension information does not include any tol-erances, then lead length and mounting hole dimen-sions are minimum values. All other dimensions aremaximum.4 Rev. 7, 07-Jan-03

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Additional InformationDocument Number 84067 www.vishay.com

Not for new developments: This heading indicatesthat the device concerned should not be used inequipment under development. It is, however, avail-able for devices presently in production.Rev. 7, 07-Jan-03 5

Basic Definitions