+5V Clean power supply - very small area

We have a design where we receive +5V supply from a PC power supply. We need to regulate this supply to provide a very clean +5V to our ADC \ DAC front end. We expect the absolute maximum current draw will be 50mA.

We have very little room so we are looking for, lets say, a LDO or something similar that can provide us we the cleanest possible +5V in the smallest possible PCB area. Possibly we should take a device that has a spec of 70-80 mA just for headroom but if there is a difference in solution area we could go down to 50mA ? Can you help us ?