BC556B, BC557, A, B, C, BC558B, C

http://onsemi.com

6

Figure 13. Thermal Response

t, TIME (ms)

1.0

2.0

5.0

1.0

0.5

0.2

0.1

0.7

0.5

0.3

0.2

0.1

0.07

0.05

0.03

0.02

0.01

20

50

10

200

500

100

1.0k

2.0k

5.0k

10

Figure 14. Active Region – Safe Operating Area

VCE, COLLECTOR-EMITTER VOLTAGE (V)

-200

-1.0

TA = 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

TJ = 25°C

D CURVES APPLY FOR POWER

PULSE TRAIN SHOWN

t1

t2

P(pk)

DUTY CYCLE, D = t1/t2

-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 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 14 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 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.