IRFB7746PBF_15 Datasheet, PDF (6/10 Pages) International Rectifier – Brushed motor drive applications

IRFB7746PbF
10
1
D = 0.50
0.20
0.10
0.1
0.05
0.02
0.01
0.01
SINGLE PULSE
( THERMAL RESPONSE )
0.001
1E-006
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
1
t1 , Rectangular Pulse Duration (sec)
Fig 14. Maximum Effective Transient Thermal Impedance, Junction-to-Case
1000
Allowed avalanche Current vs avalanche
pulsewidth, tav, assuming Tj = 125°C and
Tstart = 25°C (Single Pulse)
100
10
Allowed avalanche Current vs avalanche
pulsewidth, tav, assuming j = 25°C and
Tstart = 125°C.
1
1.0E-06
1.0E-05
1.0E-04
1.0E-03
tav (sec)
Fig 15. Avalanche Current vs. Pulse Width
1.0E-02
1.0E-01
120
TOP
Single Pulse
BOTTOM 1.0% Duty Cycle
100
ID = 35A
80
60
40
20
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
23a, 23b.
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 = tav ·f
Z_thJC(D, t_av) = Transient thermal resistance, see Figures 13)
PD (ave) = 1/2 ( 1.3·BV·I_av) = T/ Z_thJC
I_av = 2T/ [1.3·BV·Z_th]
E_{AS (AR)} = P_{D (ave)·}t_av
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November 7, 2014