There are three main reasons for chips to break down
First, overheating breakdown:
The overheating breakdown here refers to the thermal breakdown that occurs when the working current does not exceed the rated current of the chip, and the reason for this breakdown is mainly that the auxiliary cooling device of the thyristor is not working well and the temperature of the controllable silicon chip is too high
2. Overvoltage breakdown:
Overvoltage breakdown is one of the main reasons for chip breakdown, the chip's ability to withstand overvoltage is almost no time, even in a few milliseconds of overvoltage will be broken down in a short period of time, so the actual application circuit, at both ends of the chip must be connected to the RC absorption loop to avoid a variety of irregular interference pulse caused by the instant overvoltage. If chip breakdown occurs frequently, check whether the components of the absorption loop are burned out or fail.
Third, overcurrent and overheating breakdown:
In fact, overcurrent breakdown and overheat breakdown are the same thing. Overcurrent breakdown is that the current produces a thermal effect inside the chip when passing through the thyristor chip, so that the chip temperature rises, and the chip will fail and cannot be recovered when the chip temperature reaches 175 ° C. Under normal conditions of use, as long as the working current does not exceed the rated current of the thyristor, this thermal breakdown will not occur, because the overcurrent breakdown principle is caused by the temperature rise, and the temperature rise process takes a certain amount of time, so in a short period of time (a few hundred milliseconds to a few seconds) is generally not a breakdown.
Too high temperature, too high voltage, and too high current will puncture the chip.
Usually the external temperature is too high, the voltage is unstable or too large, and the current is too large, resulting in chip breakdown. The working environment of ordinary chips is about 0-70 degrees, and the military will not exceed 150 degrees, and the external temperature will cause chip damage. The chip is generally low voltage, and too much voltage is easy to cause chip breakdown. If the instantaneous current is too large, it is easier to break down the chip instantaneously.