INPUT BUFFER FOR SEMICONDUCTOR DEVICE

摘要

PURPOSE: An input buffer for a semiconductor device is provided to carried out its normal operation even in the case that a random voltage between a first potential and a second potential is supplied as an external reference voltage. CONSTITUTION: The input buffer comprises voltage shift circuits(1,2) and a differential amplifier(3). The voltage shift circuit(1) transforms an external reference voltage(VR) to a first signal(V1) predetermined while the voltage shift circuit(2) transforms an external signal(VI) obtained by superposing a small amplitude logic signal on the reference voltage(VR) to a second voltage(V2) obtained by superposing a complementary signal of a small amplitude logic signal on the first signal. And the differential amplifier(3) supplies a signal(V0) to an internal circuit where the signal(V0) results from comparing the potential of the first signal(V1) with that of the second signal(V2). Consequentially the input buffer is capable of operating in its normal mode even when a random potential ranging from 1.25V to 2.9V is supplied as the external reference voltage.