Abstract: An analog switch and an analog multiplexer are realized by which electron charges which have been stored in a stray capacitance provided on the output side thereof before a switch is conducted do not give an adverse influence to a level of such an analog input voltage which is subsequently entered after the switch has been switched. An analog switch circuit is arranged by insulating gate type transistors and a voltage follower which is parallel-connected to these insulating type transistors. When the analog switch circuit is turned ON, the voltage follower is firstly brought into an active state, and thereafter, these insulating gate type transistors are brought into conductive conditions.
Abstract: In order to improve the performance of a semiconductor integrated circuit device wherein a capacitor provided between storage nodes of an SRAM and a device having an analog capacitor are formed on a single substrate, a plug is formed in a silicon oxide film on a pair of n channel type MISFETs in a memory cell forming area, and a local wiring LIc for connecting respective gate electrodes and drains of the pair of n channel type MISFETs is formed over the silicon oxide film and the plug. Thereafter, a capacitive insulating film and an upper electrode are further formed over the local wiring LIc. According to the same process step as the local wiring, capacitive insulating film and upper electrode formed in the memory cell forming area, a local wiring LIc, a capacitive insulating film and an upper electrode are formed over a silicon oxide film in an analog capacitor forming area and a plug in the silicon oxide film.
Abstract: A semiconductor memory capable of reducing refresh cycle time, which includes normal memory cells provided at predetermined intersections of plural normal word lines and plural bit lines, and redundant memory cells of redundant word lines and the plural bit lines, a redundancy relief circuit evaluates whether each of an internal address signal for a memory operation and a refresh address signal corresponds to the address of a defective word line of the plural normal word lines. An address selecting circuit switches the defective word line to a redundant word line according to the evaluation result. The redundancy relief circuit then evaluates whether a refresh address added to the refresh address signal corresponds to a defective address, and during refresh, the address selecting circuit selects a normal or redundant word line according to the evaluation result in a preceding cycle.
Type:
Grant
Filed:
July 11, 2002
Date of Patent:
July 13, 2004
Assignees:
Renesas Technology Corporation, Hitachi ULSI Systems Co., Ltd.