Datasheet
IRFP4868PbF
5 www.irf.com © 2012 International Rectifier October 30, 2012
1E-006 1E-005 0.0001 0.001 0.01 0.1 1
t
1
, Rectangular Pulse Duration (sec)
0.0001
0.001
0.01
0.1
1
T
h
e
r
m
a
l
R
e
s
p
o
n
s
e
(
Z
t
h
J
C
)
°
C
/
W
0.20
0.10
D = 0.50
0.02
0.01
0.05
SINGLE PULSE
( THERMAL RESPONSE )
Notes:
1. Duty Factor D = t1/t2
2. Peak Tj = P dm x Zthjc + Tc
1.0E-06 1.0E-05 1.0E-04 1.0E-03 1.0E-02 1.0E-01
tav (sec)
0.1
1
10
100
1000
A
v
a
l
a
n
c
h
e
C
u
r
r
e
n
t
(
A
)
0.05
Duty Cycle = Single Pulse
0.10
Allowed avalanche Current vs avalanche
pulsewidth, tav, assuming
j = 25°C and
Tstart = 150°C.
0.01
Allowed avalanche Current vs avalanche
pulsewidth, tav, assuming
Tj = 150°C and
Tstart =25°C (Single Pulse)
Fig 13. Maximum Effective Transient Thermal Impedance, Junction-to-Case
Fig 14. Typical Avalanche Current vs. Pulsewidth
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 as Tjmax is not
exceeded.
3. Equation below based on circuit and waveforms shown in Figures
16a, 16b.
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 Tjmax
(assumed as 25°C in Figure 14, 15).
t
av
= Average time in avalanche.
D = Duty cycle in avalanche = tav ·f
Z
thJC
(D, t
av
) = Transient thermal resistance, see Figures 13)
P
D (ave)
= 1/2 ( 1.3·BV·I
av
) = T/ Z
thJC
I
av
= 2T/ [1.3·BV·Z
th
]
E
AS (AR)
= P
D (ave)
·t
av
25 50 75 100 125 150 175
Starting T
J
, Junction Temperature (°C)
0
200
400
600
800
1000
1200
E
A
R
,
A
v
a
l
a
n
c
h
e
E
n
e
r
g
y
(
m
J
)
TOP Single Pulse
BOTTOM 1.0% Duty Cycle
I
D
= 42A
Fig 15. Maximum Avalanche Energy vs. Temperature