I am trying to find a 2.5V voltage reference, but the only part available in the library I HAVE to use is a 2.5V LDO regulator. I need to have the 2.5V reference supplied from a varying 10 to 16 V source. What are other methods besides a zener or band-gap reference device that I can design a voltage reference with? I was thinking of just using 4 0.6V drop diodes forward biased in series to get a 2.4V drop with a current limiting resistor. Is this feasible and why wouldn't I see this more often if it is?