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IRFB3806PBF Datasheet, PDF (5/11 Pages) International Rectifier – HEXFETPower MOSFET
IRFB/S/SL3806PbF
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D = 0.50
0.20
0.10
0.1
0.05
0.02
0.01
0.01
0.001
1E-006
SINGLE PULSE
( THERMAL RESPONSE )
1E-005
0.0001
τJ τJ
τ1 τ1
R1R1
Ci= τi/Ri
Ci τi/Ri
R2R2
τ2 τ2
R3R3 Ri (°C/W) τi (sec)
τCτ 0.6086 0.00026
τ3 τ3
0.9926 0.001228
0.5203 0.00812
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
100
Duty Cycle = Single Pulse
0.01
10
0.05
0.10
Allowed avalanche Current vs avalanche
pulsewidth, tav, assuming ∆Tj = 150°C and
Tstart =25°C (Single Pulse)
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Allowed avalanche Current vs avalanche
pulsewidth, tav, assuming ∆Τj = 25°C and
Tstart = 150°C.
0.1
1.0E-06
1.0E-05
1.0E-04
1.0E-03
1.0E-02
tav (sec)
Fig 14. Typical Avalanche Current vs.Pulsewidth
1.0E-01
80
TOP
Single Pulse
Notes on Repetitive Avalanche Curves , Figures 14, 15:
(For further info, see AN-1005 at www.irf.com)
BOTTOM 1.0% Duty Cycle
1. Avalanche failures assumption:
ID = 25A
60
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.
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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
20
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)
0
25 50 75 100 125 150 175
Starting TJ , Junction Temperature (°C)
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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