Материал: MJ10007R

MJ10007

The Safe Operating Area figures shown in Figures 11 and 12 are specified ratings for these devices under the test conditions

Figure 11. Forward Bias Safe Operating Area

VCE, COLLECTOR±EMITTER VOLTAGE (VOLTS)

Figure 12. Reverse Bias Switching

Safe Operating Area

SAFE OPERATING AREA INFORMATION

FORWARD BIAS

There are two limitations on the power handling ability of a transistor: average junction temperature and second breakdown. 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 dissipation than the curves indicate.

The data of Figure 11 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 derate the same as thermal limitations. Allowable current at the voltages shown on Figure 11 may be found at any case temperature by using the appropriate curve on Figure 13.

TJ(pk) may be calculated from the data in Figure 10. 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 VCEX(sus) at a given collector current and represents a voltage±current condition that can be sus-

tained during reverse biased turn±off. This rating is verified under clamped conditions so that the device is never subjected to an avalanche mode. Figure 12 gives the complete reverse bias safe operating area characteristics.