IRFP4368PbF
1
0.1
D = 0.50
0.20
0.10
0.05
R1
R1
R2
R2
R3
R3
R4
R4
Ri (°C/W) τi (sec)
0.01
0.02
0.01
0.0145
0.0661
0.1257
0.0838
0.000024
0.000148
0.002766
0.017517
τ
τ
J τJ
τ
Cτ
1τ1
Ci= τi/Ri
τ
τ
τ
2τ2
3τ3
4τ4
0.001
0.0001
SINGLE PULSE
( THERMAL RESPONSE )
Notes:
1. Duty Factor D = t1/t2
2. Peak Tj = P dm x Zthjc + Tc
1E-006
1E-005
0.0001
0.001
0.01
0.1
t
, Rectangular Pulse Duration (sec)
1
Fig 13. Maximum Effective Transient Thermal Impedance, Junction-to-Case
1000
100
10
Duty Cycle = Single Pulse
Allowed avalanche Current vs avalanche
pulsewidth, tav, assuming Tj = 150°C and
∆
0.01
Tstart =25°C (Single Pulse)
0.05
0.10
Allowed avalanche Current vs avalanche
pulsewidth, tav, assuming
Tstart = 150°C.
j = 25°C and
∆Τ
1
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
1.0E-01
tav (sec)
Fig 14. Typical Avalanche Current vs.Pulsewidth
500
400
300
200
100
0
Notes on Repetitive Avalanche Curves , Figures 14, 15:
(For further info, see AN-1005 at www.irf.com)
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.
4. PD (ave) = Average power dissipation per single avalanche pulse.
5. BV = Rated breakdown voltage (1.3 factor accounts for voltage increase
during avalanche).
6. Iav = Allowable avalanche current.
7. ∆T = Allowable rise in junction temperature, not to exceed Tjmax (assumed as
25°C in Figure 14, 15).
tav = Average time in avalanche.
D = Duty cycle in avalanche = tav ·f
TOP
BOTTOM 1.0% Duty Cycle
= 195A
Single Pulse
I
D
ZthJC(D, tav) = Transient thermal resistance, see Figures 13)
PD (ave) = 1/2 ( 1.3·BV·Iav) = DT/ ZthJC
25
50
75
100
125
150
175
Iav = 2DT/ [1.3·BV·Zth]
Starting T , Junction Temperature (°C)
EAS (AR) = PD (ave)·tav
J
Fig 15. Maximum Avalanche Energy vs. Temperature
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5
INFINEON [ Infineon ]
