Abstract: An input buffer particularly suitable for a semiconductor device includes a CMOS inverter for buffering an input signal which varies between first and second logic levels and producing an output signal at an output node thereof which is the logical inverse of the input signal, and a compensation circuit for compensating the output signal for fluctuations thereof which are due to fluctuations of a supply voltage. The CMOS inverter preferably includes a pull-up MOS transistor having a gate, a first electrode coupled to a supply voltage, and a second electrode, and a pull-down MOS transistor having a gate, a first electrode coupled to a reference voltage, and a second electrode.