The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 14, 1989
Filed:
Jan. 12, 1987
Youichi Matsumoto, Kodaira, JP;
Ryuuji Shibata, Higashiyamato, JP;
Isamu Kobayashi, Tokyo, JP;
Satoshi Meguro, Tokyo, JP;
Kouichi Nagasawa, Kunitachi, JP;
Hideo Meguro, Tachikawa, JP;
Hisahiro Moriuchi, Tanashi, JP;
Masahiro Ogata, Akishima, JP;
Kikuo Sakai, Fussa, JP;
Toshifumi Takeda, Kodaira, JP;
Hitachi Ltd., Tokyo, JP;
Hitachi VLSI Engineering Corp., Tokyo, JP;
Abstract
A mask-programmed ROM includes depletion type load MOSFETs provided between data lines in a memory array and a power supply voltage, the MOSFETs having a ground potential of the circuit applied to their gates. Reading of data is carried out by an amplifying MOSFET which supplies a current to a selected data line through a depletion type MOSFET which is supplied at its gate with the circuit ground potential. Thus, bias voltages which are respectively applied to the data lines and a sense amplifier which receives a signal read out from a selected data line are made equal to each other, thereby achieving a high-speed read operation.