How to take the minimum numbers from an array PHP

I have a problem with retrieving numbers from an array,
For e.g, I will have an array like this

[20, 25, 40, 50, 30, 45, 33, 25]

I would like to retrieve the first 3 minimum numbers from the array.
Neither too big nor too small and not to be duplicated
For e.g ouput will be

[20, 25, 33]