BUD42D

http://onsemi.com

9

Figure 28. Forward Bias Safe Operating Area

10

0.01

1000

100

10

Figure 29. Reverse Bias Safe Operating Area

5

3

0

700

500

400

300

GAIN ≥ 4

600

1

0.1

4

2

1

10 ms

1 ms

1 ms

5 ms

dc

MAXIMUM RATINGS

Figure 30. Power Derating

1

0

160

40

20

0.6

0.2

60

80

100

120

140

0.4

0.8

SECOND BREAKDOWN

DERATING

THERMAL DERATING

There are two limitations on the power handling ability of

a transistor: average junction temperature and second

limits of the transistor that must be observed for reliable

operation; i.e., the transistor must not be subjected to greater

dissipation than the curves indicate. The data of Figure 28 is

level. Second breakdown pulse limits are valid for duty

Breakdown limitations do not derate like thermal

limitations. Allowable current at the voltages shown on

Figure 28 may be found at any case temperature by using the

appropriate curve on Figure 30.

case temperatures, thermal limitations will reduce the power

that can be handled to values less than the limitations

imposed by second breakdown. For inductive loads, high

voltage and current must be sustained simultaneously during

turn−off with the base to emitter junction reverse biased. The

safe level is specified as reverse biased safe operating area

(Figure 29). This rating is verified under clamped conditions

so that the device is never subjected to an avalanche mode.