We are looking for an appropriate low-noise, low-drop voltage regulator to
power the 16-bit ADC AD7626. Which device is a better fit : ADP3334 (5V, 2.5V)
or ADP7104 (5V, 2.5V)? Is there any other voltage regulator that is more
suitable than those both devices?
For the 2.5V rails I suggest that you use the ADP151 low noise LDO for the
lowest noise solution. For a lower dropout voltage the ADP124/125 will work at
the expense of higher output noise. If two 2.5Vout LDOs are needed (VDD2 & VIO)
we have the dual output ADP223.
For the 5V rail you will need the higher Vin ADP7102 or ADP7104, they have
fixed 5Vout options. This assumes power source greater than 5.5V.