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IRFB3207 Datasheet, PDF (5/11 Pages) International Rectifier – HEXFET Power MOSFET
IRF/B/S/SL3207
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D = 0.50
0.1
0.20
0.10
0.05
0.01
0.02
0.01
0.001
0.0001
1E-006
SINGLE PULSE
( THERMAL RESPONSE )
1E-005
0.0001
τJ τJ
τ1 τ1
R1R1
Ci= τi/Ri
Ci i/Ri
R2R2
τCτ
τ2 τ2
Ri (°C/W) τi (sec)
0.2151 0.001175
0.2350 0.017994
Notes:
1. Duty Factor D = t1/t2
2. Peak Tj = P dm x Zthjc + Tc
0.001
0.01
0.1
t1 , Rectangular Pulse Duration (sec)
Fig 13. Maximum Effective Transient Thermal Impedance, Junction-to-Case
10000
Duty Cycle = Single Pulse
1000
100
0.01
0.05
10
0.10
Allowed avalanche Current vs
avalanche pulsewidth, tav
assuming ∆Tj = 25°C due to
avalanche losses. Note: In no
case should Tj be allowed to
exceed Tjmax
1
1.0E-06
1.0E-05
1.0E-04
1.0E-03
tav (sec)
Fig 14. Typical Avalanche Current vs.Pulsewidth
1.0E-02
1.0E-01
1000
TOP
Single Pulse
BOTTOM 1% Duty Cycle
800
ID = 75A
600
400
200
0
25
50
75
100 125 150 175
Starting TJ , Junction Temperature (°C)
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
ZthJC(D, tav) = Transient thermal resistance, see Figures 13)
PD (ave) = 1/2 ( 1.3·BV·Iav) = DT/ ZthJC
Iav = 2DT/ [1.3·BV·Zth]
EAS (AR) = PD (ave)·tav
Fig 15. Maximum Avalanche Energy vs. Temperature
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