INPUT BUFFER FOR SEMICONDUCTOR MEMORY

摘要

PROBLEM TO BE SOLVED: To provide an input buffer for a semiconductor memory. SOLUTION: The buffer comprises a differential amplifier 21 for amplifying the difference between a reference voltage DREF and external applied input signal INPUT and switching unit 21 for selecting and transferring an external power feed voltage EVC to the amplifier 21 under the condition of an SSTL interface where the reference voltage VREF and signal INPUT dependently vary according to the feed voltage EVC, or for selecting and transferring an internal power feed voltage IVC to the amplifier 21 under the condition of an LVTTL interface where the reference voltage VREF and signal INPUT hold const. levels, irrespective of the variation of the feed voltage EVC, thus operating stably.