INPUT BUFFER CIRCUIT OF SEMICONDUCTOR MEMORY

PROBLEM TO BE SOLVED: To improve a margin in a high input range and the one in a low input range by making a logical threshold voltage lower when an external voltage level is high and by making it higher when the external voltage level is low. SOLUTION: A signal LVCC comes to be in a high state when a first external voltage divided in a prescribed ratio is a reference voltage or below and to be in a low state when it is the reference voltage or above. An external voltage sensing part 100 outputs this signal and a signal HVCC which comes to be in the high state when a second external voltage divided in the prescribed ratio is the reference value or below and to be in the low state when it is the reference value or above. A buffer 200 converts an input signal of a TTL level into a signal of a CMOS level on the basis of the output signals HVCC and LVCC of the external voltage sensing part 100. According to this configuration, a margin in a high input range and the one in a low input range are improved.