# Unity gain op-amp buffer, single supply - potential problems?

I need to precision buffer a DC (or slow changing) voltage of around 2.5V using an opamp in non-inverting unity gain mode and driven from a single supply using no resistors. Supply voltage is 5V. Is it enough just to wire it as described? Opamp chosen is OPA2188.

Potential problems I can see are PSU noise being introduced, which may mean special power supply decoupling. Any others?

With power supply at 5V you are left with a max common mode voltage of 3.5V. In non-inverting configuration the inverting input will sit at about 2.5V so you only have 1V headroom. If your supply lowers just a bit you risk malfunctioning. And even if it stays stiff at 5V, note that those specs are given with an $R_L=10k\Omega$ (see above the table). So if you use the opamp as a buffer your load could have lower resistance and this could impact the max common mode voltage tolerated by the opamp.