How to understand this parameter in the MOS tube specification?

kal9623287

How to understand this parameter in the MOS tube specification? [Copy link]

How to understand the SOA curve parameters in the MOS tube specification ?

How to read the SOA curve? What does it mean by safe working area ? Can any teacher tell me? Thank you

maychang

SOA is the safe operating area, the horizontal axis is the voltage between the drain and source, and the vertical axis is the drain current.

Therefore, any point in the figure is the drain voltage and drain current (instantaneous value). If the point falls within the safe zone, the MOS tube is safe.

maychang

The safety zone is bounded by several curves. The area marked with DC is the smallest, and within this range, the drain voltage and drain current can continue and are both safe. The area marked with time is larger, and the shorter the time, the larger the area, which means that the pulse duration is short and the safety range is large, that is, a larger drain voltage and drain current are allowed. However, no matter how short the time is, the maximum drain voltage (green in the figure) and the maximum drain current (red in the figure) must not be exceeded.

maychang

When the MOS tube is working, its drain voltage and drain current are constantly changing. In other words, the point representing the working state is constantly moving in the diagram. During the movement, it is not allowed to go outside the safe zone (a considerable margin is required in actual applications), otherwise the MOS tube will be damaged.

kal9623287

maychang posted on 2022-5-30 14:41 The safe zone is bounded by several curves. The area marked DC is the smallest. Within this range, the drain voltage and drain current can continue and are safe. The time marked...

Thank you teacher for your answer

There is a problem

For example, the 1ms curve on the SOA curve, when VDS is 200V, corresponds to the ID current. I want to ask whether this current is the maximum current that this MOS tube can withstand when it is connected for 1ms?

Also, the corresponding VDS refers to the voltage across DS when the mos is turned off?

maychang

kal9623287 posted on 2022-5-31 13:33 Thank you for the answer. For example, the 1ms curve on the SOA curve, when VDS is 200V, the corresponding ID current, I want to ask the current is this m ...

Each point on the plane has voltage on the horizontal axis and current on the vertical axis. The position of the point is the power. The boundary framed by the 1ms curve actually limits the power dissipated by the MOS tube. Of course, given the voltage and power, the current is also limited. If the current does not change within 1ms, this current value is the maximum current that the MOS tube can withstand within this 1ms.

maychang

kal9623287 posted on 2022-5-31 13:33 Thank you for the answer. For example, the 1ms curve on the SOA curve, when VDS is 200V, the corresponding ID current, I want to ask the current is this m ...

"Also, the corresponding VDS refers to the voltage across DS when the MOS is turned off?"

No. It refers to the voltage across the MOS tube DS in this state .

Each point on the plane in the figure represents a working state of the MOS tube. The point representing the off state is roughly the horizontal axis (close to the horizontal axis, the current is approximately zero).

xjtburden

Safe operating area, the boundary area between voltage and current? I don't know if it's correct.

kal9623287

maychang posted on 2022-5-31 14:05 "Also, does the corresponding VDS refer to the voltage across DS when the mos is turned off? " No. It refers to the voltage across DS of the MOS tube in this state. In the figure...

Thank you for your guidance

Understood