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6
Motorola Bipolar Power Transistor Device Data
I
0.005
Figure 12. Forward Bias Safe Operating Area
6
VCE, COLLECTOR–EMITTER VOLTAGE (VOLTS)
10
50
50
10
5
2
1
0.2
0.1
450
20
100
Figure 13. RBSOA, Reverse Bias Switching
Safe Operating Area
VCE, COLLECTOR–EMITTER VOLTAGE (VOLTS)
0
100
200
16
8.0
20
300
IC/IB
≥
5
VBE(off) = 5 V
TJ = 100
°
C
I
0.05
200
350
400 500
12
4.0
0.02
0.01
400
500
dc
1 ms
10
μ
s
100
μ
s
600
600
20
MJ13333
BONDING WIRE LIMIT
THERMAL LIMIT @ TC = 25
°
C
(SINGLE PULSE)
SECOND BREAKDOWN LIMIT
SAFE OPERATING AREA INFORMATION
FORWARD BIAS
There are two limitations on the power handling ability of a
transistor average junction temperature and second break-
down. 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 dissipa-
tion than the curves indicate.
The data of Figure 12 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 der-
ate the same as thermal limitations. Allowable current at the
voltages shown on Figure 12 may be found at any case tem-
perature by using the appropriate curve on Figure 14.
TJ(pk) may be calculated from the data in Figure 11. At high
case temperatures, thermal limitations will reduce the power
that can be handled to values less than the limitations im-
posed by second breakdown.
REVERSE BIAS
For inductive loads, high voltage and high current must be
sustained simultaneously during turn–off, in most cases, with
the base to emitter junction reverse biased. Under these
conditions the collector voltage must be held to a safe level
at or below a specific value of collector current. This can be
accomplished by several means such as active clamping,
RC snubbing, load line shaping, etc. The safe level for these
devices is specified as Reverse Bias Safe Operating Area
and represents the voltage–current condition allowable dur-
ing reverse biased turn–off. This rating is verified under
clamped conditions so that the device is never subjected to
an avalanche mode. Figure 13 gives the complete RBSOA
characteristics.
0
Figure 14. Power Derating
TC, CASE TEMPERATURE (
°
C)
0
40
80
80
40
100
120
P
160
200
60
20
THERMAL
DERATING
FORWARD BIAS
SECOND BREAKDOWN
DERATING