JPS57120299A - Read-only memory - Google Patents

Read-only memory

Info

Publication number
JPS57120299A
JPS57120299A JP550881A JP550881A JPS57120299A JP S57120299 A JPS57120299 A JP S57120299A JP 550881 A JP550881 A JP 550881A JP 550881 A JP550881 A JP 550881A JP S57120299 A JPS57120299 A JP S57120299A
Authority
JP
Japan
Prior art keywords
fet
stored
read
fet20
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
JP550881A
Other languages
Japanese (ja)
Inventor
Toru Akiyama
Tamotsu Maeda
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.)
Sanyo Electric Co Ltd
Sanyo Denki Co Ltd
Original Assignee
Sanyo Electric Co Ltd
Sanyo Denki 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 Sanyo Electric Co Ltd, Sanyo Denki Co Ltd filed Critical Sanyo Electric Co Ltd
Priority to JP550881A priority Critical patent/JPS57120299A/en
Publication of JPS57120299A publication Critical patent/JPS57120299A/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 obtain an ROM which has large storage capacity and small area by varying the threshold voltage of each FET of a memory cell so that >=3 states are stored in each FET. CONSTITUTION:Each FET20, constituent unit of an ROM, is provided with one of >=3 threshold voltage relating to logical values to be stored, thus storing logical values, which exceed one bit, correspondingly. For the reading of it, >=2 reference voltages are applied successively to the gate of one selected FET to read the stored logical value of the FET. For example, a staircase wave varying in level successively is supplied from a staircase wave generating circuit 4 by timing signals t1-t3 to the FET20 whose gate connects with lead lines a0-a3 selected by address input signals A0 and A1, and the data line output of a memory cell array 2 is read through a sense amplifier 3 and a selecting circuit 5.
JP550881A 1981-01-17 1981-01-17 Read-only memory Pending JPS57120299A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP550881A JPS57120299A (en) 1981-01-17 1981-01-17 Read-only memory

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP550881A JPS57120299A (en) 1981-01-17 1981-01-17 Read-only memory

Publications (1)

Publication Number Publication Date
JPS57120299A true JPS57120299A (en) 1982-07-27

Family

ID=11613131

Family Applications (1)

Application Number Title Priority Date Filing Date
JP550881A Pending JPS57120299A (en) 1981-01-17 1981-01-17 Read-only memory

Country Status (1)

Country Link
JP (1) JPS57120299A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0634750A2 (en) * 1993-07-12 1995-01-18 Kabushiki Kaisha Toshiba 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

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0634750A2 (en) * 1993-07-12 1995-01-18 Kabushiki Kaisha Toshiba Apparatus and method for reading multi-level data stored in a semiconductor memory
EP0634750A3 (en) * 1993-07-12 1996-01-10 Toshiba Kk Apparatus and method for reading multi-level data stored in a semiconductor memory.
US5852575A (en) * 1993-07-12 1998-12-22 Kabushiki Kaisha Toshiba 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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