An output buffer with process and temperature compensation comprises an enable terminal, a clock generator, a PMOS threshold voltage detector, an NMOS threshold voltage detector, a first comparator, a second comparator, a first compensation code generator, a second compensation code generator and an output buffer stage, wherein the output buffer stage has an output stage, the output buffer stage means for controlling a drive current generated by the output stage, wherein the output stage has a first voltage output terminal, and the modulated drive current is capable of compensating slew rate of the first voltage output terminal.