What do isolation voltage/thickness, creepage, and clearance mean?

These terms are defined as follows.

- Isolation voltage
It indicates the maximum value of the AC voltage that can be applied between the input pin and the output pin, expressed as a root mean square (r.m.s) value. The measurement conditions are normally Ta = 25°C, RH = 60%, with application of the rated AC voltage between all input-side pins and all output-side pins for 1 minute.

- Creepage distance
It indicates the minimum distance between the two conductors (input pin, output pin) along the insulating material.

- Isolation thickness
It indicates the minimum thickness of the insulating material between the two conductors (input, output).

- Clearance
It indicates the minimum distance between the two conductors (input pin, output pin) in the atmosphere.

For details about the above three terms, go to the following URL.

https://www.renesas.com/products/optoelectronics/technology/standard-p.html