IXYS POWER MOSFETs Datasheet Definition

1 ixys PowerMOSFET Datasheet Parameters DefinitionAbdus Sattar, ixys CorporationIXAN00651 ixys providesdatasheets with parametersthat areessential andusefulforselectingthe appropriate device as well asfor predetectingits performance in anapplication. Thegraphs included in the Datasheet representtypical performancecharacteristicandcan be used to extrapolate from one set of operating conditions toanother. POWER MOSFET generally contains a bodydiode, whichprovides freewheeling operation intheinductive load 1 shows the equivalentcircuitforanN-Channelanda P-Channel POWER 1: (a)anN-Channel (b)a P-Channel Enhancement-Mode POWER MOSFET1 EssentialRatings andCharacteristics1. MaximumRatingsThe ratings are limiting values for a deviceand validfor the whole range of TJandTJMThe junction temperature(JT) range is-55 ~ 150oC in most cases andit is thedevice s permissible temperaturerangewithin which the device may beoperatedcontinuously. The maximum junction temperature (JMT) is 150oC unlessotherwise specified(in some cases 175oC).

2 Junction temperature varies electricalparametersof POWER MOSFET, for example, atvery low temperature (<-55oC),the device can loss itsfunctionalityand atvery high temperature,the device sthreshold voltage becomes very lowandleakage current becomes very high. Italso cancause thermal run awaywithin the deviceat very high TemperatureTStgIt is the range of temperaturefor storage or transportation of the dev ice and itmust be between-55 ~ Temperature TLIt is the maximum leadtemperatureduring soldering and it must not exceed300oC for 10 seconds at 1/8 from the PDIXYS PowerMOSFET Datasheet Parameters DefinitionAbdus Sattar, ixys CorporationIXAN00652 The POWER dissipation is the maximumcalculatedpower that the device candissipate and is function of both on the maximum junction temperature and thethermal resistance at a case [TJ M TC]/RthJC(1) Drain Current ID25 This is the maximum current rating for the deviceat a case temperature(TC)25oC . It is calculated based on maximum POWER dissipation, maximum on-resistance and temperature dependence of on-resistance.

3 It canbe limited by thecurrent handling capacity of IDRMSThis is the maximum current ratingofthe device s lead at a case Current IDMIt is the peak current the device can flow above ID25specification under themaximum junction temperature. It varies with current pulse widths, duty cycleand heat dissipation Forward Current ISIt s the maximum DC current the diode can flow in the forward direction atspecified case Diode ForwardCurrent ISMIt s thepeakcurrent the diode can flowabove ISspecification under the maximumjunction Drain-Source Voltage VDSSThis is defined as the maximumdrain-source voltage without causing avalanchebreakdown with gate-source short-circuited (VGS= 0) and the device is at avalanche breakdown voltage is temperature dependent and could be lessthan theBVDSS, VGSThis is the maximumvoltage that can be introduced between gate and source. Itdepends on the thickness and characteristics of the gate oxide layer. The actualgate oxide withstand voltage is typically much higher than this but varies due tomanufacturing processes, so staying within this rating ensures ofRise ofOff -stateVoltage (dv/dt)This isdefined as the maximum permissible rate of rise of off-state voltage acrossthe Energy(for avalanche devices) ,RepetitiveIARIXYS PowerMOSFET Datasheet Parameters DefinitionAbdus Sattar, ixys CorporationIXAN00653 For POWER MOSFETs , the propensity for current crowding in the die area duringavalanche mandates a limit in avalanche current.

4 It represents the avalancheenergy specification for thedevice andthetrue capability of a repetitiveAvalanche Energy, Single Pulse EARThe maximum permissible reverse-voltagebreakdown energy in continuousoperationwhile observing the maximum permissiblechip heatdissipation limits the avalanche non-repetitiveAvalanche Energy, EASThe maximum permissible reverse-voltagebreakdown energy in continuousoperationwhile observing the maximum permissiblechip heatdissipation limitsthe avalanche Mechanical provides the mechanical size of the device with package provides the weight information of the devicewith TorqueMdThis provides the maximum permissibletorque that can be applied on the devicefor CharacteristicsAccording to IEC 60747-8:2004, the characteristics of POWER MOSFETs are given at25 Coand at one specified higher operating IGSSIt is the maximum gate-source leakage current with the drain and thesourceshortedandwiththe introduction of rated gate-source IDSSIt is the maximum drain-source leakage current with the gate and the sourceshortedandwith the introduction of rated drain-source Down Voltage BVDSST hebreakdown voltageBVDSSis the minimum blocking voltage between thedrain and the source at given drain currentand when the gate is shorted to break down voltage has a positive temperature Threshold VoltageVGS (th)It is the gate-source voltage at which the drain current starts to flowand thedevice is considered at ON-State.

5 It has negative temperature PowerMOSFET Datasheet Parameters DefinitionAbdus Sattar, ixys on-state voltageVGSMThis is agate-source maximum voltage in the On-state ResistanceRDS (on)The specific on-resistance for a POWER MOSFET is defined byRDS (on)= RSOURCE+ RCH+ RA+ RD+ RJ+ Rsub+ Rwcml,(2)Where,RSOURCE= Source diffusion resistanceRCH= Channel resistanceRA= Accumulation resistanceRJ= JFET component resistanceRD= Drift region resistanceRsub= Substrate resistanceRwcml= Bond wire TransconductancegfsIt is defined as the change in drain current divided by the change in gate voltagefor a constant drain large transconductance is desirable to obtain a highcurrent handling capabilitywith low gate drive voltage and for achieving highfrequency Capacitances andGate Capacitance CissThe input capacitance is measured between the gate and source terminals with thedrain shorted to the source terminal. The Cissis made up of the gate-to -draincapacitance CDGin parallel with the gate-to -source capacitance CGS+CDG(3) Transfer Capacitance CrssThe reverse transfer capacitance is measured between the drain and gate terminalswith the source connected to ground.

6 The reverse transfer capacitance is the sameas the gate-to -drain capacitance CDG(4) Capacitance CossThe output capacitance is measured between the drain and source with the gateshorted to the source terminal. The Cossis equal to the drain-to -source capacitanceCDS, in parallel with the gate to drain capacitance CDS+CDG(5) ChargesIt s the total gate charge that s required to raise the gate-source voltage to 15 Vinmost casesto fully turn-on the device. It smeasured at a specified drain current, ixys PowerMOSFET Datasheet Parameters DefinitionAbdus Sattar, ixys CorporationIXAN00655drain-source voltage and gate-source gatechargereflects the chargestored on the inter-terminal capacitances described earlier and is used in designingth e gate drive Switching times(td (on),tr,td (off),tf) Delay Time td (on)The turn-on delay time is defined as the time interval when the gate-sourcevoltage(VGS) has reached 10 % of its end value (VGG), to the time when the drain-source voltage(VDS) hasdropped to 90 % of its initial value (VDD).

7 Time trFollowing the turn-on delay time, the rise-time follows; it is the interval betweenthe drain-source voltages from 90% to 10% of its initial value. The drain currentstarts to rise and the major part of turn-on losses is generated during this Delay Time td (off)Theturn-off delay timeis definedas the time interval between the moment whenthe gate-emitter voltage (VGE) has declined to 90% of its initial value (VGG) andthe drain-source voltage has risen to 10 % of the supply voltage Time tfFollowing the turn-off delay time, the fall-time follows; it is the interval betweenthe drain-source voltage rises from 10% to 90% of its end value. During thisperiod, the drain current starts to fall and the major part of turn-off losses isgenerated during this Turn-on energy (per pulse) Eonwhere Turn-off energy (per pulse) Eoffwhere Thermal Characteristic2 PowerMOSFETs operate at elevated junction temperature and it is important toobserve their thermal limitations in order toachieveacceptable performance to CaseRthJCIt s the thermal resistance from the junction of the die to the outside of the devicecase.

8 Itdescribes the passage of heat between thesemiconductorchipand specifies maximum static to HeatsinkRthCKThe thermal resistancecaseto sinkcharacterizes the static heat dissipation of aMOSFET and depends on module size, heatsink, case surfaces, thicknessparameters of thermal layersbetween module and Diode Forward Voltage VSDThe forward voltage is the maximum forward drop of theintrinsicdiodeat aspecified value of source PowerMOSFET Datasheet Parameters DefinitionAbdus Sattar, ixys CorporationIXAN00656 Reverse recovery timeis the time interval starting as current flow reversesthrough the diode until it goes zero. ixys shows typical trrat given recoverychargeis the integral of the reverse recovery current that occursduring current recoverychargeis the integral of the reverse recovery current thatoccurs during current DefinitionsFigure2: Output Characteristicsof a POWER MOSFET[IXTH/IXTQ130N10T]51. Output Characteristics:Figure2 shows a typical output characteristic of an N-Channel POWER MOSFET in whichthe different modes of operation are delineated.

9 In the Cut-off region, the gate-sourcevoltage (VGS) is less than the gate-threshold voltage (VGS(th)) and the device is an open-circuit or the Ohmic region, the device acts as a resistor with almost a constant on-resistance RDS (on)and is equal to the linear-mode of operation, the deviceoperates in the Current-Saturated region where the drain current (Ids) is a function of thegate-source voltage (Vgs) and defined by: ixys PowerMOSFET Datasheet Parameters DefinitionAbdus Sattar, ixys CorporationIXAN00657)()()(2)(thGSGS fsthGSGSDSVVgVVKI (6)Where K is a parameter depending on the temperature and device geometry and gfsis thecurrent gain or transconductance. When the drain voltage (VDS) is increased, the positivedrain potential opposes the gate voltage bias and reduces the surface potential in thechannel. The channel inversion layer charge decreases with increasingVDSandultimately, it becomes zero when the drain voltage equals to)()(thGSGSVV.

10 This point iscalled the channel pinch-off point where the drain current becomes : Normalized RDS(on)vs. Junction Temperature[IXTH/IXTQ130N10T]52. On-ResistanceRDS(on) Temperature:Temperature has a strong effecton RDS(on), on-resistance, which isan importantparameter in POWER MOSFET anda measure of the current handling capability of important merit is an increase intheon-resistancewith increasing temperatureas shown inFigure3, which portrays a positive temperature coefficient. The positivetemperature coefficient of RDS (on)is anice feature when paralleling POWER MOSFET sbecause it ensures thermal PowerMOSFET Datasheet Parameters DefinitionAbdus Sattar, ixys CorporationIXAN00658 Figure4: Drain Current vs. Case Temperature [IXTH/IXTQ130N10T]53. DrainCurrent Temperature:The drain current IDis a rating ofthe maximum continuous DC current with the die at itsmaximum rated junction temperature (TJM) and the case at 25oC.