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IRFB7430PBF Datasheet, PDF (6/8 Pages) International Rectifier – HEXFETPower MOSFET
1
0.1
0.01
D = 0.50
0.20
0.10
0.05
0.02
0.01
IRFB7430PBF
0.001
0.0001
1E-006
SINGLE PULSE
( THERMAL RESPONSE )
1E-005
0.0001
0.001
Notes:
1. Duty Factor D = t1/t2
2. Peak Tj = P dm x Zthjc + Tc
0.01
0.1
t1 , Rectangular Pulse Duration (sec)
Fig 14. Maximum Effective Transient Thermal Impedance, Junction-to-Case
1000
100
Allowed avalanche Current vs avalanche
pulsewidth, tav, assuming Tj = 150°C and
Tstart =25°C (Single Pulse)
10
Allowed avalanche Current vs avalanche
pulsewidth, tav, assuming  j = 25°C and
Tstart = 150°C.
1
1.0E-06
1.0E-05
1.0E-04
1.0E-03
tav (sec)
Fig 15. Typical Avalanche Current vs.Pulsewidth
1.0E-02
1.0E-01
800
TOP
Single Pulse
Notes on Repetitive Avalanche Curves , Figures 14, 15:
(For further info, see AN-1005 at www.irf.com)
700
600
BOTTOM 1.0% Duty Cycle
ID = 100A
1. Avalanche failures assumption:
Purely a thermal phenomenon and failure occurs at a temperature far in
excess of Tjmax. This is validated for every part type.
2. Safe operation in Avalanche is allowed as long asTjmax is not exceeded.
3. Equation below based on circuit and waveforms shown in Figures 16a, 16b.
500
4. PD (ave) = Average power dissipation per single avalanche pulse.
5. BV = Rated breakdown voltage (1.3 factor accounts for voltage increase
400
during avalanche).
6. Iav = Allowable avalanche current.
300
7. T = Allowable rise in junction temperature, not to exceed Tjmax (assumed as
25°C in Figure 14, 15).
200
tav = Average time in avalanche.
D = Duty cycle in avalanche = tav ·f
100
ZthJC(D, tav) = Transient thermal resistance, see Figures 13)
0
25 50 75 100 125 150 175
Starting TJ , Junction Temperature (°C)
Fig 16. Maximum Avalanche Energy vs. Temperature
PD (ave) = 1/2 ( 1.3·BV·Iav) = DT/ ZthJC
Iav = 2DT/ [1.3·BV·Zth]
EAS (AR) = PD (ave)·tav
2014-8-10
6
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