MJE5850 Datasheet, PDF (5/8 Pages) Motorola, Inc – 8 AMPERE PNP SILICON POWER TRANSISTORS 300- 350- 400 VOLTS 80 WATTS

SWITCHING TIMES NOTE
MJE5850 MJE5851 MJE5852
In resistive switching circuits, rise, fall, and storage times
have been defined and apply to both current and voltage
waveforms since they are in phase. However, for inductive
loads which are common to SWITCHMODE power supplies
and hammer drivers, current and voltage waveforms are not
in phase. Therefore, separate measurements must be made
on each waveform to determine the total switching time. For
this reason, the following new terms have been defined.
tsv = Voltage Storage Time, 90% IB1 to 10% VCEM
trv = Voltage Rise Time, 10 – 90% VCEM
tfi = Current Fall Time, 90 – 10% ICM
tti = Current Tail, 10 – 2% ICM
tc = Crossover Time,10% VCEM to 10% ICM
An enlarged portion of the inductive switching waveform is
shown in Figure 7 to aid on the visual identity of these terms.
For the designer, there is minimal switching loss during
storage time and the predominant switching power losses
occur during the crossover interval and can be obtained us-
ing the standard equation from AN–222A:
]^{PSWT = 1/2 VCCIC(tc)f}
In general, trv + tfi tc. However, at lower test currents this
relationship may not be valid.
As is common with most switching transistors, resistive
switching is specified at 25°C and has become a benchmark
for designers. However, for designers of high frequency con-
verter circuits, the user oriented specifications which make
this a “SWITCHMODE” transistor are the inductive switching
speeds (tc and tsv) which are guaranteed at 100_C.
1.0
0.7
0.5
0.3
0.2
0.1
0.07
0.05
0.03
0.02
0.01
0.1
VCC = 250 V
IC/IB = 4
TJ = 25°C
tr
td
0.2 0.3 0.5 0.7 1.0
2.0 3.0 5.0 7.0 10
IC, COLLECTOR CURRENT (AMPS)
Figure 9. Turn–On Switching Times
10
0.7
0.4
0.3
0.2
0.1
0.1
ts
VCC = 250 V
IC/IB = 4
VBE(off) = 5 V
TJ = 25°C
tf
0.3 0.5 0.7 1.0
2.0
4.0 7.0 10
IC, COLLECTOR CURRENT (AMPS)
Figure 10. Turn–Off Switching Time
1
0.7
D = 0.5
0.5
0.3
0.2
0.1
0.07
0.05
0.03
0.02
0.01
0.01
0.2
0.1
0.05
0.02
0.01
SINGLE PULSE
0.02
0.05 0.1 0.2
0.5 1
Z_θJC(t) = r(t) R_θJC
R_θJC = 1.25°C/W MAX
D CURVES APPLY FOR POWER
PULSE TRAIN SHOWN
READ TIME AT t1
TJ(pk) – TC = P(pk) Z_θJC(t)
2
5 10 20
50
t, TIME (ms)
Figure 11. Typical Thermal Response [Z_θJC(t)]
P(pk)
t1
t2
DUTY CYCLE, D = t1/t2
100 200
500 1 k
Motorola Bipolar Power Transistor Device Data
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