3
Motorola Bipolar Power Transistor Device Data
Figure 4. Thermal Response
t, TIME OR PULSE WIDTH (ms)
1.0
0.01
0.01
0.7
0.5
0.3
0.2
0.1
0.07
0.05
0.03
0.02
0.02
r(t) EFFECTIVE TRANSIENT
THERMAL RESISTANCE (NORMALIZED)
0.05 0.1 0.2 0.5 1.0 2.0 5.0 10 20 50 100 200 1000500
R
θ
JC(max) = 1.92
°
C/W
D CURVES APPLY FOR POWER
PULSE TRAIN SHOWN
READ TIME AT t1
TJ(pk) – TC = P(pk) R
θ
JC(t)
P(pk)
t1t2
DUTY CYCLE, D = t1/t2
D = 0.5
SINGLE PULSE
0.2
0.05
0.1
0.02
0.01
SINGLE
PULSE
0.03 0.3 3.0 30 300
SECOND BREAKDOWN LIMITED
BONDING WIRE LIMITED
THERMAL LIMITATION @ TC = 25
°
C
CURVES APPLY BELOW RATED VCEO
10
5.0
Figure 5. Active Region Safe Operating Area
5.0
1.0
0.1 10 20 60 100
TJ = 150
°
C
BD243B, BD244B
BD243C, BD244C
5.0 ms
0.5 ms
0.2
2.0
0.5
IC, COLLECTOR CURRENT (AMP)
VCE, COLLECTOR–EMITTER VOLTAGE (VOLTS)
3.0
0.3
40 80
1.0
ms
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 5 is based on TJ(pk) = 150
_
C: TC is
variable depending on conditions. Second breakdown pulse
limits are valid for duty cycles to 10% provided TJ(pk)
v
150
_
C, TJ(pk) may be calculated from the data in Fig-
ure 4. At high case temperatures, thermal limitations will
reduce the power that can be handled to values less than the
limitations imposed by second breakdown.
5.0
0.06
Figure 6. Turn-Off Time
IC, COLLECTOR CURRENT (AMP)
t, TIME ( s)
µ
2.0
1.0
0.5
0.3
0.2
0.1
0.07
0.05 0.1 0.2 0.4 0.6 2.0 6.0
TJ = 25
°
C
VCC = 30 V
IC/IB = 10
IB1 = IB2
ts
1.0 4.0
0.7
3.0
tf
300
0.5
Figure 7. Capacitance
VR, REVERSE VOLTAGE (VOLTS)
30 1.0 2.0 3.0 5.0 20 30 5010
CAPACITANCE (pF)
200
100
70
50
TJ = 25
°
C
Cib
Cob