Semiconductor memory device having redundancy configuration with read circuit for defective memory address

摘要

A semiconductor memory device having a redundancy configuration including a read circuit for a defective memory address. The read circuit includes a transistor which forms a current switch circuit with a bipolar-transistor of an input buffer circuit. The base electrode of the transistor is connected to the output terminal of a PROM which stores a defective address. The reading operation is carried out by applying a voltage lower than a normally applied voltage to the base electrode of the bipolar-transistor and detecting the base current.