MJD44H11 MJD45H11

3

Motorola Bipolar Power Transistor Device Data

t, TIME (ms)

1

0.01

1 k

0.3

0.2

0.07

R

θJC(t) = r(t) RθJC

R

θJC = 6.25°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

0.01

0.7

Figure 1. Thermal Response

0.5

0.1

0.05

0.03

0.02

0.02 0.03

0.05

0.1

0.2 0.3

0.5

1

2

3

5

10

20

30

50

100

200 300

500

0.2

SINGLE PULSE

D = 0.5

0.1

0.02

0.01

0.05

20

1

VCE, COLLECTOR–EMITTER VOLTAGE (VOLTS)

0.02

3

100

2

0.5

5

0.1

THERMAL LIMIT @ TC = 25°C

WIRE BOND LIMIT

5

7

20

70

10

100

µs

dc

0.05

0.3

1

3

10

50

30

Figure 2. Maximum Forward Bias

Safe Operating Area

1 ms

500

µs

5 ms

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 2 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 1. 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.

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

Figure 3. Power Derating

TC

TA

SURFACE

MOUNT