PXX time in datasheets

[kirill578]

Hey, There is some sort of time constant in datasheets between pulses like P5A or P15, I've attached an image of it.
What does it mean and how do I convert it to seconds.(I could not find any expiation of it in the datasheet itself).

here is the datasheet:
http://ww1.microchip.com/downloads/en/DeviceDoc/39622L.pdf

[Psi]

Bottom of the datasheet, page 42 and 43.

It lists all the Pxx values in 2 tables and shows their timing requirements.
P5A has to be more than 40ns