Datasheet IRF4905SPbF, IRF4905LPbF (Infineon) - 7

IRF4905S/L 1000 Duty Cycle = Single Pulse 100 ) A Allowed avalanche Current vs ( 0.01 t avalanche pulsewidth, tav ner assuming ∆Tj = 25°C due to ru 0.05 avalanche losses. Note: In no C 10 e 0.10 case should Tj be allowed to hc exceed Tjmax nalavA 1 0.1 1.0E-06 1.0E-05 1.0E-04 1.0E-03 1.0E-02 1.0E-01 tav (sec)
Fig 15.
Typical Avalanche Current Vs.Pulsewidth 160
Notes on Repetitive Avalanche Curves , Figures 15, 16:
TOP Single Pulse
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BOTTOM 1% Duty Cycle 1. Avalanche failures assumption: )J I Purely a thermal phenomenon and failure occurs at a D = -42A m( 120 temperature far in excess of Tjmax. This is validated for y every part type. gre 2. Safe operation in Avalanche is allowed as long asTjmax is n E not exceeded. eh 3. Equation below based on circuit and waveforms shown in 80 cn Figures 12a, 12b. ala 4. PD (ave) = Average power dissipation per single v A avalanche pulse. , 5. BV = Rated breakdown voltage (1.3 factor accounts for R 40 A voltage increase during avalanche). E 6. Iav = Allowable avalanche current. 7. ∆T = Allowable rise in junction temperature, not to exceed Tjmax (assumed as 25°C in Figure 15, 16). 0 tav = Average time in avalanche. 25 50 75 100 125 150 D = Duty cycle in avalanche = tav ·f Starting T ZthJC(D, tav) = Transient thermal resistance, see figure 11) J , Junction Temperature (°C)
PD (ave) = 1/2 ( 1.3·BV·Iav) =
D
T/ ZthJC Fig 16.
Maximum Avalanche Energy
Iav = 2
D
T/ [1.3·BV·Zth]
Vs. Temperature
EAS (AR) = PD (ave)·tav
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