IRFB5615PbF
www.irf.com 5
Fig 13. Maximum Avalanche Energy Vs. Drain Current
Fig 12. On-Resistance Vs. Gate Voltage
Fig 14. Typical Avalanche Current Vs.Pulsewidth
Fig 15. Maximum Avalanche Energy Vs. Temperature
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 T
jmax
. This is validated for
every part type.
2. Safe operation in Avalanche is allowed as long as neither
Tjmax nor Iav (max) is exceeded
3. Equation below based on circuit and waveforms shown in
Figures 17a, 17b.
4. P
D (ave)
= Average power dissipation per single
avalanche pulse.
5. B
V
= 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 14, 15).
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
4 6 8 10 12 14 16 18 20
V
GS,
Gate -to -Source Voltage (V)
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
R
D
S
(
o
n
)
,
D
r
a
i
n
-
t
o
-
S
o
u
r
c
e
O
n
R
e
s
i
s
t
a
n
c
e
(
Ω
)
I
D
= 21A
T
J
= 25°C
T
J
= 125°C
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
)
0.05
Duty Cycle = Single Pulse
0.10
Allowed avalanche Current vs avalanche
pulsewidth, tav, assuming ∆Τ 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)
25 50 75 100 125 150 175
Starting T
J
, Junction Temperature (°C)
0
50
100
150
200
250
300
350
400
450
500
E
A
S
,
S
i
n
g
l
e
P
u
l
s
e
A
v
a
l
a
n
c
h
e
E
n
e
r
g
y
(
m
J
)
I
D
TOP 2.8A
5.3A
BOTTOM 21A
25 50 75 100 125 150 175
Starting T
J
, Junction Temperature (°C)
0
20
40
60
80
100
120
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
= 21A
