0.5 1.0 2.0 7.00.3 3.0 5.00.7 IC, COLLECTOR CURRENT (AMPERES)
Figure 4. Turn–Off Time
10
t, TIME ( s)
µ
7.0
5.0
3.0
2.0
1.0
0.7
0.5
0.3
0.2
0.1 10 20 30
TJ = 25
°
C
VCC = 30 V
IC/IB = 10
IB1 = IB2
ts
tf
(PNP)
(NPN)
ts
tf
IC, COLLECTOR CURRENT (AMPS)
hFE, DC CURRENT GAIN
Figure 5. DC Current Gain
200
500
0.2 0.5 2.0 1000.1
100
50
20
10
1.0
VCE = 4.0 V
TJ = 25
°
C
5.0
10 205.0 50
PNP
NPN
1000
2.0
1.0
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 6 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
w
25
_
C. Second breakdown limitations do not der-
ate the same as thermal limitations.
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 conditions during re-
verse biased turn–off. This rating is verified under clamped
conditions so that the device is never subjected to an ava-
lanche mode. Figure 7 gives RBSOA characteristics.