Abstract: An input buffer is provided which can function as either a voltage referenced input buffer or a non-voltage referenced input buffer. The input buffer includes a circuit which is selectively configurable in one of the two different modes of operation in response to a mode signal, wherein in a first mode of operation a reference signal is operative to constrain a trip point of the input buffer. A single circuit with a capability of fulfilling both roles allows the decision as to which mode of input buffer is to be used to be deferred until it has been determined which mode is most suitable for a particular application.