MJ16018 MJW16018

5

Motorola Bipolar Power Transistor Device Data

100

0

TC, CASE TEMPERATURE (°C)

0

40

200

80

60

40

20

MJ16018

MJW16018

80

120

160

Figure 15. Power Derating

SECOND BREAKDOWN

DERATING

THERMAL

DERATING

SAFE OPERATING AREA INFORMATION

FORWARD BIAS

There are two limitations on the power handling ability of a

transistor: average junction temperature and second break-

down. Safe operating area curves indicate IC – VCE limits of

the transistor that must be observed for reliable operation;

i.e., the transistor must not be subjected to greater dissipa-

tion than the curves indicate.

The data of Figure 13 is based on TC = 25_C; TJ(pk) is

variable depending on power level. Second breakdown pulse

limits are valid for duty cycles to 10% but must be derated

when TC ≥ 25_C. Second breakdown limitations do not der-

ate the same as thermal limitations. Allowable current at the

voltages shown on Figure 13 may be found at any case tem-

perature by using the appropriate curve on Figure 15.

TJ(pk) may be calculated from the data in Figure 16. At

high case temperatures, thermal limitations will reduce the

power that can be handled to values less than the limitations

imposed by second breakdown.

REVERSE BIAS

For inductive loads, high voltage and high current must be

sustained simultaneously during turn–off, in most cases, with

the base–to–emitter junction reverse biased. Under these

conditions the collector voltage must be held to a safe level

at or below a specific value of collector current. This can be

accomplished by several means such as active clamping,

RC snubbing, load line shaping, etc. The safe level for these

devices is specified as Reverse Bias Safe Operating Area

and represents the voltage current condition allowable dur-

ing reverse biased turnoff. This rating is verified under

clamped conditions so that the device is never subjected to

an avalanche mode. Figure 14 gives the RBSOA character-

istics.

t, TIME (ms)

1.0

0.01

0.01

0.7

0.2

0.1

0.05

0.02

1.0

2.0

5.0

10

20

50

100

200

500

R

θJC(t) = r(t) RθJC

R

θJC = 1.0°C/W MAX

D CURVES APPLY FOR POWER

PULSE TRAIN SHOWN

READ TIME @ t1

TJ(pk) – TC = P(pk) R

θJC(t)

P(pk)

t1

t2

DUTY CYCLE, D = t1/t2

D = 0.5

0.2

0.01

SINGLE PULSE

0.1

0.1

0.5

0.2

1.0 k

Figure 16. Thermal Response

0.5

0.3

0.07

0.03

0.02

0.05

0.02

0.05