IRF60R217
6
2016-01-05
Fig 14. Maximum Effective Transient Thermal Impedance, Junction-to-Case
Fig 16. Maximum Avalanche Energy vs. Temperature
Fig 15. Avalanche Current vs. Pulse Width
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 Figures 14, 15).
t
av
= Average time in avalanche.
D = Duty cycle in avalanche = tav ·f
Z
thJC
(D, t
av
) = Transient thermal resistance, see Figure 14)
PD (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
1E-006 1E-005 0.0001 0.001 0.01 0.1
t
1
, Rectangular Pulse Duration (sec)
0.001
0.01
0.1
1
10
T
h
e
r
ma
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
25 50 75 100 125 150 175
Starting T
J
, Junction Temperature (°C)
0
20
40
60
80
100
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
= 35A
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
A
v
a
l
a
n
c
h
e
C
u
r
r
e
n
t
(
A
)
Allowed avalanche Current vs avalanche
pulsewidth, tav, assuming
j = 25°C and
Tstart = 150°C.
Allowed avalanche Current vs avalanche
pulsewidth, tav, assuming
Tj = 150°C and
Tstart = 25°C (Single Pulse)