IRF3805S-7PPBF_15 Datasheet, PDF (7/11 Pages) International Rectifier – Advanced Process Technology

IRF3805S/L-7PPbF
1000
100
10
Duty Cycle = Single Pulse
0.01
0.05
0.10
Allowed avalanche Current vs avalanche
pulsewidth, tav, assuming ∆ Tj = 150°C and
Tstart =25°C (Single Pulse)
Allowed avalanche Current vs avalanche
pulsewidth, tav, assuming ∆Τ j = 25°C and
Tstart = 150°C.
1
1.0E-06
1.0E-05
1.0E-04
tav (sec)
1.0E-03
1.0E-02
1.0E-01
Fig 15. Typical Avalanche Current vs.Pulsewidth
500
TOP
Single Pulse
BOTTOM 1% Duty Cycle
400
ID = 140A
300
200
100
0
25
50
75 100 125 150 175
Starting TJ , Junction Temperature (°C)
Fig 16. Maximum Avalanche Energy
vs. Temperature
Notes on Repetitive Avalanche Curves , Figures 15, 16:
(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 T_jmax. This is validated for
every part type.
2. Safe operation in Avalanche is allowed as long asT_jmax is
not exceeded.
3. Equation below based on circuit and waveforms shown in
Figures 12a, 12b.
4. P_{D (ave)} = Average power dissipation per single
avalanche pulse.
5. BV = Rated breakdown voltage (1.3 factor accounts for
voltage increase during avalanche).
6. I_av = Allowable avalanche current.
7. ∆T = Allowable rise in junction temperature, not to exceed
T_jmax (assumed as 25°C in Figure 15, 16).
t_{av =} Average time in avalanche.
D = Duty cycle in avalanche = t_av ·f
Z_thJC(D, t_av) = Transient thermal resistance, see figure 11)
P_{D (ave)} = 1/2 ( 1.3·BV·I_av) = DT/ Z_thJC
I_av = 2DT/ [1.3·BV·Z_th]
E_{AS (AR)} = P_{D (ave)}·t_av
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