BCW72LT1G(2009) View Datasheet(PDF) - ON Semiconductor
Part Name
Description
Manufacturer
BCW72LT1G Datasheet PDF : 7 Pages
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BCW72LT1G
1.0
0.7
0.5
D = 0.5
0.3
0.2
0.2
0.1
0.1
0.07
0.05
0.05
0.02
0.03
0.02
0.01
SINGLE PULSE
0.01
0.01 0.02 0.05 0.1 0.2 0.5 1.0 2.0
P(pk)
FIGURE 19A
t1
t2
DUTY CYCLE, D = t1/t2
D CURVES APPLY FOR POWER
PULSE TRAIN SHOWN
READ TIME AT t1 (SEE AN−569)
ZqJA(t) = r(t) • RqJA
TJ(pk) − TA = P(pk) ZqJA(t)
5.0 10 20 50 100 200
t, TIME (ms)
500 1.0 k 2.0 k 5.0 k 10 k 20 k 50 1k00 k
Figure 19. Thermal Response
104
DESIGN NOTE: USE OF THERMAL RESPONSE DATA
VCC = 30 Vdc
103
A train of periodical power pulses can be represented by the model
as shown in Figure 19A. Using the model and the device thermal
response the normalized effective transient thermal resistance of
102
ICEO
Figure 19 was calculated for various duty cycles.
To find ZqJA(t), multiply the value obtained from Figure 19 by the
101
steady state value RqJA.
Example:
100
ICBO
The MPS3904 is dissipating 2.0 watts peak under the following
AND
conditions:
10-1
ICEX @ VBE(off) = 3.0 Vdc
t1 = 1.0 ms, t2 = 5.0 ms. (D = 0.2)
Using Figure 19 at a pulse width of 1.0 ms and D = 0.2, the reading of
r(t) is 0.22.
10-2
-4 -2
00
The peak rise in junction temperature is therefore
0 + 20 + 40 + 60 + 80 + 100 + 120 + 140 + 160 DT = r(t) x P(pk) x RqJA = 0.22 x 2.0 x 200 = 88°C.
TJ, JUNCTION TEMPERATURE (°C)
For more information, see AN−569.
Figure 19A.
400
200
100
60
40
20
10
6.0
4.0
2.0
1.0 ms 100 ms
TC = 25°C
TA = 25°C
dc
10 ms
1.0 s
dc
TJ = 150°C
CURRENT LIMIT
THERMAL LIMIT
SECOND BREAKDOWN LIMIT
4.0 6.0 8.0 10
20
VCE, COLLECTOR-EMITTER VOLTAGE (VOLTS)
Figure 20.
The safe operating area curves indicate IC−VCE limits of the
transistor that must be observed for reliable operation. Collector load
lines for specific circuits must fall below the limits indicated by the
applicable curve.
The data of Figure 20 is based upon TJ(pk) = 150°C; TC or TA is
variable depending upon conditions. Pulse curves are valid for duty
cycles to 10% provided TJ(pk) ≤ 150°C. TJ(pk) may be calculated from
the data in Figure 19. At high case or ambient temperatures, thermal
limitations will reduce the power that can be handled to values less
than the limitations imposed by second breakdown.
40
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