MJD2955 MJD3055

4

Motorola Bipolar Power Transistor Device Data

Figure 6. “On” Voltages, MJD2955

2

0.1

0

0.2 0.3

0.5

1

3

10

0.8

1.6

1.2

0.4

5

TJ = 25°C

VBE(sat) @ IC/IB = 10

VCE(sat) @ IC/IB = 10

VBE @ VCE = 3 V

Figure 7. Switching Time Test Ciruit

Figure 8. Thermal Response

t, TIME (ms)

1

0.01

0.02

0.7

0.2

0.1

0.05

0.02

0.05

1

2

5

10

20

50

100

200

500

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

D = 0.5

0.2

0.05

0.02

0.01

SINGLE PULSE

0.1

0.1

0.5

0.2

1 k

0.5

0.3

0.07

0.03

0.03

0.3

3

30

300

IC, COLLECTOR CURRENT (AMP)

2

+11 V

25

µs

0

–9 V

RB

–4 V

D1

SCOPE

VCC

+ 30 V

RC

tr, tf ≤ 10 ns

DUTY CYCLE = 1%

51

D1 MUST BE FAST RECOVERY TYPE, eg:

1N5825 USED ABOVE IB ≈ 100 mA

MSD6100 USED BELOW IB ≈ 100 mA

RB and RC VARIED TO OBTAIN DESIRED CURRENT LEVELS

0.01

Figure 9. Maximum Forward Bias

Safe Operating Area

0.01

VCE, COLLECTOR–EMITTER VOLTAGE (VOLTS)

0.02

5

2

1

10

0.5

0.1

TJ = 150°C

1ms

dc

3

0.3

0.6

1

2

60

20

40

WIRE BOND LIMIT

THERMAL LIMIT TC = 25°C (D = 0.1)

SECOND BREAKDOWN LIMIT

10

6

4

500

µs

0.03

0.05

100

µs

5ms

FORWARD BIAS SAFE OPERATING AREA

INFORMATION

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 9 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 8. 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.