MJE18204 Datasheet, PDF (7/12 Pages) Motorola, Inc – POWER TRANSISTORS 5 AMPERES 1200 VOLTS 35 and 75 WATTS

TYPICAL STATIC CHARACTERISTICS
MJE18204 MJF18204
1.0
SECOND
0.8
BREAKDOWN
DERATING
0.6
0.4
0.2
THERMAL
DERATING
0
20 40
60
80 100 120 140 160
TC, CASE TEMPERATURE (°C)
Figure 19. Forward Bias Power Derating
There are two limitations on the power handling ability of
a transistor: average junction temperature and second
breakdown. Safe operating area curves indicate IC–VCE
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 19 is based on TC = 25°C; TJ(pk) is variable
depending on power level. Second breakdown pulse limits
are valid for duty cycles to 10% but must be derated when
TC > 25°C. Second breakdown limitations do not derate the
same as thermal limitations. Allowable current at the
voltages shown on Figure 16 may be found at any case
temperature by using the appropriate curve on Figure 18.
TJ(pk) may be calculated from the data in Figures 21 and
22. 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 induc-
tive 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 17). This rating
is verified under clamped conditions so that the device is
never subjected to an avalanche mode.
TYPICAL SWITCHING CHARACTERISTICS
(IB1 = IB2 FOR ALL CURVES)
VCE
dyn 1 µs
0V
dyn 3 µs
90% IB
1 µs
IB
3 µs
TIME
Figure 20. Dynamic Saturation
Voltage Measurements
10
9
IC
8
7
90% IC
tfi
tsi
6
5 ^Vclamp
4
10% Vclamp
10% IC
tc
3
IB 90% IB1
2
1
0
0
1
2
3
4
5
6
7
8
TIME
Figure 21. Inductive Switching Measurements
Motorola Bipolar Power Transistor Device Data
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