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JPS57181497A - Read only memory - Google Patents

Read only memory

Info

Publication number
JPS57181497A
JPS57181497A JP6673381A JP6673381A JPS57181497A JP S57181497 A JPS57181497 A JP S57181497A JP 6673381 A JP6673381 A JP 6673381A JP 6673381 A JP6673381 A JP 6673381A JP S57181497 A JPS57181497 A JP S57181497A
Authority
JP
Japan
Prior art keywords
trs
information
valve
storage
rom
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP6673381A
Other languages
Japanese (ja)
Inventor
Hiromitsu Yagi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd
Priority to JP6673381A priority Critical patent/JPS57181497A/en
Publication of JPS57181497A publication Critical patent/JPS57181497A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11C—STATIC STORES
    • G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
    • G11C11/56—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using storage elements with more than two stable states represented by steps, e.g. of voltage, current, phase, frequency
    • G11C11/5692—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using storage elements with more than two stable states represented by steps, e.g. of voltage, current, phase, frequency read-only digital stores using storage elements with more than two stable states
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11C—STATIC STORES
    • G11C11/00—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor
    • G11C11/56—Digital stores characterised by the use of particular electric or magnetic storage elements; Storage elements therefor using storage elements with more than two stable states represented by steps, e.g. of voltage, current, phase, frequency

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Read Only Memory (AREA)

Abstract

PURPOSE:To achieve an ROM possible for storage of information having three valve or more, by using MOS transistors (TRs) with different threshold voltage as storage elements. CONSTITUTION:For example, MOS TRs M11, M13, M23 are set to a threshold voltage VT1, M12, M21, and M31 are to VT2 and M22, M33 and M32 are set to a VT3, and the voltages VT1-VT3 have a relation of VT1<VT2<VT3. They respectively correspond to figures 1, 2 and 3. Specified TRs M11... are selected via row lines X1... and column lines Y1... according to the selected voltage corresponding to the threshold voltages VT1-VT3 applied to the row lines X1..., and three valve etc. information are read out and through the storage of three valve or more information, the number of storage elements can be reduced for an ROM.
JP6673381A 1981-04-30 1981-04-30 Read only memory Pending JPS57181497A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6673381A JPS57181497A (en) 1981-04-30 1981-04-30 Read only memory

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6673381A JPS57181497A (en) 1981-04-30 1981-04-30 Read only memory

Publications (1)

Publication Number Publication Date
JPS57181497A true JPS57181497A (en) 1982-11-08

Family

ID=13324377

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6673381A Pending JPS57181497A (en) 1981-04-30 1981-04-30 Read only memory

Country Status (1)

Country Link
JP (1) JPS57181497A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0649147A1 (en) * 1993-10-11 1995-04-19 Texas Instruments France Increased capacity storage device
EP0634750A3 (en) * 1993-07-12 1996-01-10 Toshiba Kk Apparatus and method for reading multi-level data stored in a semiconductor memory.

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0634750A3 (en) * 1993-07-12 1996-01-10 Toshiba Kk Apparatus and method for reading multi-level data stored in a semiconductor memory.
EP0649147A1 (en) * 1993-10-11 1995-04-19 Texas Instruments France Increased capacity storage device

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