BUH150G
http://onsemi.com
9
TYPICAL THERMAL RESPONSE
Figure 21. Forward Bias Power Derating
1
0
16010020
T
C
, CASE TEMPERATURE (°C)
0.8
POWER DERATING FACTOR
0.6
0.4
0.2
60 140
SECOND BREAKDOWN
DERATING
40 80 120
THERMAL DERATING
There are two limitations on the power handling ability of
a transistor: average junction temperature and second
breakdown. Safe operating area curves indicate I
C
−V
CE
limits of the transistor that must be observed for reliable
operation; i.e., the transistor must not be subjected to greater
dissipation than the curves indicate. The data of Figure 22 is
based on T
C
= 25°C; T
J(pk)
is variable depending on power
level. Second breakdown pulse limits are valid for duty cycles
to 10% but must be derated when T
C
> 25°C. Second
breakdown limitations do not derate the same as thermal
limitations. Allowable current at the voltages shown on
Figure 22 may be found at any case temperature by using the
appropriate curve on Figure 21.
T
J(pk)
may be calculated from the data in Figure 24. At any
case temperatures, thermal limitations will reduce the power
that can be handled to values less than the limitations imposed
by second breakdown. For inductive loads, high voltage and
current must be sustained simultaneously during turn−off
with the base to emitter junction reverse biased. The safe level
is specified as a reverse biased safe operating area
(Figure 23). This rating is verified under clamped conditions
so that the device is never subjected to an avalanche mode.
Figure 22. Forward Bias Safe Operating Area
100
0.01
10001
V
CE
, COLLECTOR-EMITTER VOLTAGE (VOLTS)
Figure 23. Reverse Bias Safe Operating Area
16
6
0
800300
V
CE
, COLLECTOR-EMITTER VOLTAGE (VOLTS)
100
1
0.1
I
C
, COLLECTOR CURRENT (AMPS)
I
C
, COLLECTOR CURRENT (AMPS)
DC
5 ms
1 ms
10 ms
1 ms
8
2
GAIN ≥ 5
0 V -1.5 V
-5 V
T
C
≤ 125°C
L
C
= 4 mH
10
400 500 700600
12
4
14
10
10
EXTENDED SOA
Figure 24. Typical Thermal Response (Z
q
JC
(t)) for BUH150
1
0.01
100.10.01
t, TIME (ms)
0.1
1 100 1000
r(t), TRANSIENT THERMAL RESISTANCE
(NORMALIZED)
R
q
JC
(t) = r(t) R
q
JC
R
q
JC
= 0.83°C/W MAX
D CURVES APPLY FOR POWER
PULSE TRAIN SHOWN
READ TIME AT t
1
T
J(pk)
- T
C
= P
(pk)
R
q
JC
(t)
P
(pk)
t
1
t
2
DUTY CYCLE, D = t
1
/t
2
0.05
SINGLE PULSE
0.5
0.2
0.1
0.02
