MJE4342 MJE4343 MJE4352 MJE4353

4

Motorola Bipolar Power Transistor Device Data

t, TIME (ms)

0.01

0.02

0.05

1.0

2.0

5.0

10

20

50

100

2000

0.1

0.5

0.2

1.0

0.2

0.1

0.05

θJC(t) = r(t) θJC

θJC = 1.0°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

0.2

Figure 9. Thermal Response

0.5

D = 0.5

0.05

0.02

200

500

1000

0.1

0.02

0.01

SINGLE PULSE

100

VCE, COLLECTOR–EMITTER VOLTAGE (VOLTS)

0.1

200

50

1.0

Figure 10. Maximum Forward Bias Safe

Operating Area

5.0 ms

dc

20

150

30

20

10

7.0

5.0

3.0

MJE4342

0.2

0.5

2.0

5.0

10

50

70 100

MJE4352

MJE4343

MJE4353

SECONDARY BREAKDOWN LIMITED

THERMAL LIMIT TC = 25°C

BONDING WIRE LIMITED

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 conditions during re-

verse biased turn–off. This rating is verified under clamped

conditions so that the device is never subjected to an ava-

lanche mode. Figure 11 gives RBSOA characteristics.

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 10 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 10 may be found at any case tem-

perature by using the appropriate curve on Figure 9.

20

VCE, COLLECTOR–EMITTER VOLTAGE (VOLTS)

8.0

Figure 11. Maximum Reverse Bias Safe

Operating Area

16

120

100

80

60

40

20

MJE4342

4.0

12

140

160

180

MJE4352

MJE4343

MJE4353

TJ = 100°C

VBE(off) ≤ 5 V