How to determine whether MOS transistor is electrostatic breakdown or overcurrent burning? — SUNMATE

MOS tubes may experience two types of faults during operation: electrostatic breakdown and overcurrent burning, which require judgment and diagnosis. Below is an introduction to how to determine whether a MOS transistor is subjected to electrostatic breakdown or overcurrent burning.

1. Electrostatic breakdown

Electrostatic breakdown refers to the generation of a high electric field between the gate and source of a MOS transistor, leading to the breakdown of the gate oxide layer and resulting in faults. The characteristic of electrostatic breakdown is that the MOS transistor does not have any problems before operation, but malfunctions occur during assembly or during use; The fault is manifested as the MOS transistor losing control and unable to switch normally.

The methods for determining electrostatic discharge include:

(1) Observe whether the appearance of the MOS tube is damaged. If there is no obvious damage to the appearance, it is likely due to electrostatic breakdown.

(2) Use a multimeter for testing, connect the electrodes of the multimeter to the gate and source of the MOS transistor, and then ground the other electrode to measure the presence of ohmic resistance. If the ohmic resistance is zero or very small, it is likely to be electrostatic breakdown.

2. Overcurrent burning

Overcurrent burning refers to the MOS tube being subjected to excessive current during operation, resulting in internal damage to the tube and causing a malfunction. The characteristic of overcurrent burnout is that the MOS transistor malfunctions during operation, usually accompanied by a smell of burning or damage; The fault manifests as a loss of control of the MOS transistor and inability to switch normally.

The methods for judging overcurrent burning include:

(1) Observe the appearance of the MOS tube for obvious signs of burning or damage. If so, it is likely to be burnt out due to overcurrent.

(2) Use a multimeter for testing, connect the electrodes of the multimeter to the gate and source of the MOS transistor, and then ground the other electrode to measure the presence of ohmic resistance. If the ohmic resistance is zero or very high, it is likely to be burnt out due to overcurrent.

In summary, by observing the appearance of MOS tubes and using a multimeter for testing, it is possible to determine whether the MOS tubes are subjected to electrostatic breakdown or overcurrent burning, and to carry out corresponding repairs and replacements.