BC856ALT1G Series
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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 10k
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) = r(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, BC559
BC557
BC556
The safe operating area curves indicate I
C
−V
CE
limits
the transistor that must be observed for reliable operatio
Collector load lines for specific circuits must fall below th
limits indicated by the applicable curve.
The data of Figure 14 is based upon T
J(pk)
= 150°C; T
C
T
A
is variable depending upon conditions. Pulse curves a
valid for duty cycles to 10% provided T
J(pk)
≤ 150°C. T
J(p
may be calculated from the data in Figure 13. At high case
ambient temperatures, thermal limitations will reduce th
power that can be handled to values less than the limitatio
imposed by the secondary breakdown.
