BC556B, BC557A, B, C, BC558B
http://onsemi.com
5
Figure 13. Thermal Response
t, TIME (ms)
1.0
r(t), TRANSIENT THERMAL
2.0 5.01.00.50.20.1
RESISTANCE (NORMALIZED)
0.7
0.5
0.3
0.2
0.1
0.07
0.05
0.03
0.02
0.01
20 5010 200 500100 1.0k 2.0k 5.0k 10
Figure 14. Active Region − Safe Operating Area
V
CE
, COLLECTOR−EMITTER VOLTAGE (V)
−200
−1.0
I
C
, COLLECTOR CURRENT (mA)
T
A
= 25°C
D = 0.5
0.2
0.1
0.05
SINGLE PULSE
SINGLE PULSE
BONDING WIRE LIMIT
THERMAL LIMIT
SECOND BREAKDOWN LIMIT
3 ms
T
J
= 25°C
Z
q
JC
(t) = (t) R
q
JC
R
q
JC
= 83.3°C/W MAX
Z
q
JA
(t) = r(t) R
q
JA
R
q
JA
= 200°C/W MAX
D CURVES APPLY FOR POWER
PULSE TRAIN SHOWN
READ TIME AT t
1
T
J(pk)
− T
C
= P
(pk)
R
q
JC
(t)
t
1
t
2
P
(pk)
DUTY CYCLE, D = t
1
/t
2
−100
−50
−10
−5.0
−2.0
−5.0 −10 −30 −45 −65 −100
1 s
BC558
BC557
BC556
The safe operating area curves indicate I
C
−V
CE
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 14 is based upon T
J(pk)
= 150°C; T
C
or T
A
is
variable depending upon conditions. Pulse curves are valid for
duty cycles to 10% provided T
J(pk)
≤ 150°C. T
J(pk)
may be
calculated from the data in Figure 13. At high case or ambient
temperatures, thermal limitations will reduce the power than can
be handled to values less than the limitations imposed by second
breakdown.
