MJD340 MJD350

3

Motorola Bipolar Power Transistor Device Data

t, TIME (ms)

1

0.01

0.01

0.5

0.2

0.1

0.05

0.02

0.05

1

2

5

10

20

50

100

200

1 k

500

R

θJC(t) = r(t) RθJC

R

θJC = 8.33°C/W MAX

D CURVES APPLY FOR POWER

PULSE TRAIN SHOWN

READ TIME AT t1

TJ(pk) – TC = P(pk) θJC(t)

P(pk)

t1

t2

DUTY CYCLE, D = t1/t2

D = 0.5

0.2

0.05

SINGLE PULSE

0.1

0.7

0.3

0.07

0.03

0.02

0.1

0.5

0.2

Figure 5. Thermal Response

0.03

0.3

3

30

300

0.01

1000

10

VCE, COLLECTOR–EMITTER VOLTAGE (VOLTS)

1

20

30

50

70 100

200

500

300

500

µs

Figure 6. Active Region Safe Operating Area

200 300

500 700 1000

100

20

50

30

10

2

5

3

1 ms

dc

100

µs

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 6 is based on TJ(pk) = 150_C; TC is

variable depending on conditions. Second breakdown pulse

limits are valid for duty cycles to 10% provided TJ(pk)

v 150_C. TJ(pk) may be calculated from the data in Fig-

ure 5. At high case temperatures, thermal limitations will re-

duce the power that can be handled to values less than the

limitations imposed by second breakdown.

Figure 7. Power Derating

25

25

T, TEMPERATURE (

°C)

0

50

75

100

125

150

20

15

10

5

2.5

0

2

1.5

1

0.5

TA TC

TC

TA (SURFACE MOUNT)