A question about 555

[aman]

I have seen in some analog circuits that if we need a 2.5 V supply
there is way to do it that generate a 5V square pulse with duty cycle
1/2 and pass it through a low pass filter to get a DC 2.5V.

I was thinking of another way of generating 2.5V. Use a voltage divider
and then use an opamp buffer.

Which of the above 2 ways is a recommended way of generating 2.5V DC?

 

[aman]

I just need 2.5V to be at one of the inputs of the opamp. I will be
using the virtual ground property of opamp getting 2.5V at the other
input of the opamp also. I dont need practically any current to be
drawn by the load because after opamp theren will be only a schmitt
trigger(comparator). So that you know this is part of an water overflow
detector. Still you think the regulator or voltage divider are good
ideas for this.