
MJE13007 MJF13007
3–673
Motorola Bipolar Power Transistor Device Data
SWITCHING TIME NOTES
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 any coil driver, 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% Vclamp
trv = Voltage Rise Time, 10–90% Vclamp
tfi = Current Fall Time, 90–10% IC
tti = Current Tail, 10–2% IC
tc = Crossover Time, 10% Vclamp to 10% IC
An enlarged portion of the turn–off waveforms is shown in
Figure 13 to aid in 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 using the standard
equation from AN222A:
PSWT = 1/2 VCCIC(tc) f
Typical inductive switching times are shown in Figure 14. In
general, trv + tfi tc. However, at lower test currents this rela-
tionship 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.
SWITCHING PERFORMANCE
12
3
4
5
6
7
8 9 10
t,
T
IME
(
ns)
IC, COLLECTOR CURRENT (AMP)
Figure 11. Turn–On Time (Resistive Load)
VCC = 125 V
IC/IB = 5
IB(on) = IB(off)
TJ = 25°C
PW = 25
s
t,TIME
(ns)
23
4
5
6
7
8 9 10
IC, COLLECTOR CURRENT (AMP)
Figure 12. Turn–Off Time (Resistive Load)
1
t,TIME
(ns)
IC, COLLECTOR CURRENT (AMP)
0.1
0.2
0.3
0.5 0.7
1
2
3
5
7
10
Figure 13. Inductive Switching Measurements
TIME
Figure 14. Typical Inductive Switching Times
10000
1000
100
10
10000
100
200
500
700
1000
2000
5000
7000
10000
10
20
50
100
200
500
1000
2000
5000
VCC = 125 V
IC/IB = 5
IB(on) = IB(off)
TJ = 25°C
PW = 25
s
IC/IB = 5
IB(off) = IC/2
Vclamp = 300 V
LC = 200 H
VCC = 15 V
TJ = 25°C
ts
tf
td
tr
tc
tfi
tsv
IC
IB
Vclamp
90% IB1
90% Vclamp
90% IC
Vclamp
10%
Vclamp
10%
IC
2%
IC
tsv
trv
tfi
tti
tc