[FAQ] How to understand the Absolute Maximum Ratings of the SW Node?

The Absolute Maximum Ratings table in a device data sheet specifies DC limits to voltages or currents that may be applied to the device pins. For the SW node, the maximum voltage rating refers to the maximum voltage that can be applied before the oxide layer in the low-side MOSFET silicon begins to break down
and causes a short between the drain and source. During switching operation, the rating can be exceeded due to the operating principles of a synchronous buck
converter. This does not violate the absolute maximum rating, because the current causing the voltage excursion is applied by the output inductor during switching operation.

Some further aspects need to be considered in addition, though:

Firstly, the proper measurement technique should be used. Improper measurement techniques introduce extra noise that adds to the voltage excursions observed at the SW node. Properly measuring the SW node voltage allows the designer to observe the stress that the device actually undergoes without the distortion caused by the high-frequency rise and fall times of the SW node.

Finally, consideration should be given to a proper for the PCB layout. A good layout minimizes EMI and noise in the system.

Those points are discussed in details in the following app note:

"Understanding the Absolute Maximum Ratings of the SW Node"

The following Power Tips training video could be of use as well:

"Power Tips: Managing your DC/DC converter's switch node sensitivity"