MJE1320
5
Motorola Bipolar Power Transistor Device Data
Table 2. Inductive Load Switching
V
(BR)CEO
Inductive Switching RBSOA
L = 10 mH L = 1.1 mH L = 1.1 mH
RB2 =
R
RB2 = 0 RB2 = 0
VCC = 20 Volts VCC = 20 Volts VCC = 20 Volts
RB1 selected for desired I
B1
RB1 selected for desired I
B1
*Tektronix Scope — Tektronix
*P–6042 or 7403 or
*Equivalent Equivalent Note: Adjust –V to obtain desired V
BE(off)
at Point A.
T1
[
L
coil
(I
Cpk
)
T1 adjusted to obtain I
C(pk)
V
CC
H.P. 214
OR EQUIV.
P.G.
0
≈
–35 V
50
0.02
µ
F
+
–
20
0.02
µ
F
100
1
µ
F
500
+ –
100
+V
≈
11 V
–V
A
2N5337
2N6191
R
B1
R
B2
10
µ
F
T
1
+V
0 V
–V
A
50
*I
B
*I
C
T.U.T.
L
MR856
V
clamp
V
CC
I
C
V
CE
I
B
I
B1
I
B2
I
C(pk)
V
CE(pk)
SAFE OPERATING AREA INFORMATION
FORWARD BIAS
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 12 is based on TC = 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 TC ≥ 25_C. Second breakdown limitations do not derate the same as thermal limitations. Allowable current at the
voltages shown on Figure 12 may be found at any case temperature by using the appropriate curve on Figure 11.
T
J(pk)
may be calculated from the data in Figure 14. At
high case temperatures, thermal limitations will reduce the
power that can be handled to values less than the limitations
imposed 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 during r everse biased turnoff. This rating is verified u nder
clamped conditions so that the device is never subjected to
an avalanche mode. Figure 13 gives the RBSOA characteristics.