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Encyclopedia > EEPROM
Computer memory types
Volatile
Non-volatile

EEPROM (also written E2PROM and pronounced e-e-prom or simply e-squared), which stands for Electrically Erasable Programmable Read-Only Memory, is a type of non-volatile memory used in computers and other electronic devices to store small amounts of data that must be saved when power is removed, e.g., calibration tables or device configuration. The terms storage (U.K.) or memory (U.S.) refer to the parts of a digital computer that retain physical state (data) for some interval of time, possibly even after electrical power to the computer is turned off. ... Volatile memory refers to computer memory that must be powered to maintain its data. ... Dynamic random access memory (DRAM) is a type of random access memory that stores each bit of data in a separate capacitor within an integrated circuit. ... DDR SDRAM or double-data-rate synchronous dynamic random access memory is a type of memory integrated circuit used in computers. ... Static random access memory (SRAM) is a type of semiconductor memory. ... Z-RAM, short for zero capacitor DRAM is a new type of computer memory in development by Innovative Silicon Inc. ... TTRAM, short for Twin Transistor RAM is new type of computer memory in development by Renesas. ... The Williams tube or (more accurately) the Williams-Kilburn tube (after Freddie Williams and coworker Tom Kilburn), developed about 1946 or 1947, was a cathode ray tube used to store electronic data. ... Mercury memory of UNIVAC I (1951) Delay line memory was a form of computer memory used on some of the earliest digital computers, such as the EDSAC and UNIVAC I. // The basic concept of the delay line originated with World War II radar research, as a system to reduce clutter... Non-volatile memory, nonvolatile memory, NVM or non-volatile storage, is computer memory that can retain the stored information even when not powered. ... Read-only memory (usually known by its acronym, ROM) is a class of storage media used in computers and other electronic devices. ... D23128C PROM on the board of ZX Spectrum A programmable read-only memory (PROM) or field programmable read-only memory (FPROM) is a form of digital memory where the setting of each byte is locked by a fuse or antifuse. ... Read-only memory (ROM) is used as a storage medium in computers. ... EPROM. The small quartz window admits UV light during erasure. ... A USB flash drive. ... Ferroelectric RAM (FRAM or FeRAM) is a type of non-volatile computer memory, similar to EEPROM but based on electric field orientation and with near-unlimited number (exceeding 1010 for 5V devices and even more for 3. ... Magnetoresistive Random Access Memory (MRAM) is a non-volatile computer memory (NVRAM) technology, which has been in development since the 1990s. ... Phase-change memory (also known as PCM, PRAM, Ovonic Unified Memory and Chalcogenide RAM [C-RAM]) is a type of non-volatile computer memory. ... Wikipedia does not have an article with this exact name. ... RRAM or Resistive Random Access Memory is a new non-volatile memory type begin developed by Sharp, Samsung, Fujitsu, Spansion, Macronix, Winbond and other companies. ... Nano-RAM, is a proprietary computer memory technology from the company Nantero. ... hi i am cool xbox is all most as cool as me hi again ... A 16×16 cm area core memory plane of 128×128 bits, i. ... Bubble memory is a type of non-volatile computer memory that uses a thin film of a magnetic material to hold small magnetized areas, known as bubbles, which each store one bit of data. ... Non-volatile memory, nonvolatile memory, NVM or non-volatile storage, is computer memory that can retain the stored information even when not powered. ...


When larger amounts of more static data are to be stored (such as in USB flash drives) other memory types like flash memory are more economical. JumpDrive redirects here. ... A USB flash drive. ...


EEPROMs are realized as arrays of floating-gate transistors. It has been suggested that this article or section be merged into Floating_Gate_MOSFET. (Discuss) A cross-section of a floating-gate transistor The floating-gate transistor is a kind of transistor that is commonly used for non-volatile storage such as flash, EPROM and EEPROM memory. ...

Contents

History

In 1983, George Perlegos at Intel developed the Intel 2816, which was built on earlier EPROM technology, but used a thin gate oxide layer so that the chip could erase its own bits without requiring a UV source. Perlegos and others later left Intel to form Seeq Technology, which used on-device charge pumps to supply the high voltages necessary for programming EEPROMs.[1] Year 1983 (MCMLXXXIII) was a common year starting on Saturday (link displays the 1983 Gregorian calendar). ... Intel Corporation (NASDAQ: INTC, SEHK: 4335), founded in 1968 as Integrated Electronics Corporation, is an American multinational corporation that is best known for designing and manufacturing microprocessors and specialized integrated circuits. ... EPROM. The small quartz window admits UV light during erasure. ... A charge pump is an electronic circuit that uses capacitors as energy storage elements to create either a higher or lower voltage power source. ...


Functions of EEPROM

There are different types of electrical interfaces to EEPROM devices. Main categories of these interface types are :

How the device is operated depends on the electrical interface. A serial bus is a computer bus that sends data bit by bit down one or a few wires. ... In computing, a parallel port is an interface from a computer system where data is transferred in or out in parallel, that is, on more than one wire. ...


Serial bus devices

Most common serial interface types are SPI, I²C and 1-Wire. These three interfaces require between 2 and 4 controls signals for operation, resulting in a memory device in an 8 pin (or less) package. The Serial Peripheral Interface Bus or SPI (often pronounced es-pÄ“-Ä« [IPA: É›s pi aɪ] or spy [IPA: spaɪ]) bus is a synchronous serial data link standard named by Motorola that operates in full duplex mode. ... I²C is a multi-master serial computer bus invented by Philips that is used to attach low-speed peripherals to a motherboard, embedded system, or cellphone. ... An I-button in a plastic fob. ...


The serial EEPROM typically operates in three phases: OP-Code Phase, Address Phase and Data Phase. The OP-Code is usually the first 8-bits input to the serial input pin of the EEPROM device (or with most I²C devices, is implicit); followed by 8 to 24 bits of addressing depending on the depth of the device, then data to be read or written. Microprocessors perform operations using binary bits (on/off/1or0). ...


Each EEPROM device typically has its own set of OP-Code instructions to map to different functions. Some of the common operations on SPI EEPROM devices are: The Serial Peripheral Interface Bus or SPI (often pronounced es-pē-ī [IPA: ɛs pi aɪ] or spy [IPA: spaɪ]) bus is a synchronous serial data link standard named by Motorola that operates in full duplex mode. ...

  • Write Enable (WREN)
  • Write Disable (WRDI)
  • Read Status Register (RDSR)
  • Write Status Register (WRSR)
  • Read Data (READ)
  • Write Data (WRITE)

Other operations supported by some EEPROM devices are:

  • Program
  • Sector Erase
  • Chip Erase commands

Parallel bus devices

Parallel EEPROM devices typically have an 8-bit data bus and an address bus wide enough to cover the complete memory. Most devices have chip select and write protect pins. Some microcontrollers also have integrated parallel EEPROM. It has been suggested that this article or section be merged with embedded microprocessor. ...


Operation of a parallel EEPROM is simple and fast when compared to serial EEPROM, but these devices are larger due to the higher pin count (28 pins or more) and have been decreasing in popularity in favor of serial EEPROM or Flash.


Failure modes

There are two limitations of stored information; endurance, and data retention.


During rewrites, the gate oxide in the floating-gate transistors gradually accumulates trapped electrons. The electric field of the trapped electrons adds to the electrons in the floating gate, lowering the window between threshold voltages for zeros vs ones. After sufficient number of rewrite cycles, the difference becomes too small to be recognizable, the cell is stuck in programmed state, and endurance failure occurs. The manufacturers usually specify minimal number of rewrites being 106 or more. It has been suggested that this article or section be merged into Floating_Gate_MOSFET. (Discuss) A cross-section of a floating-gate transistor The floating-gate transistor is a kind of transistor that is commonly used for non-volatile storage such as flash, EPROM and EEPROM memory. ...


During storage, the electrons injected into the floating gate may drift through the insulator, especially at increased temperature, and cause charge loss, reverting the cell into erased state. The manufacturers usually guarantee data retention of 10 years or more.[2]


Related types

Flash memory is a later form of EEPROM. In the industry, there is a convention to reserve the term EEPROM to byte-wise writeable memories compared to block-wise writable flash memories. EEPROM takes more die area than flash memory for the same capacity because each cell usually needs both a read, write and erase transistor, while in flash memory the erase circuits are shared by large blocks of cells (often 512×8). A USB flash drive. ... Assorted discrete transistors A transistor is a semiconductor device, commonly used as an amplifier or an electrically controlled switch. ...


Newer non-volatile memory technologies such as FeRAM and MRAM are slowly replacing EEPROMs in some applications, but are expected to remain a small fraction of the EEPROM market for the foreseeable future. Ferroelectric RAM (FRAM or FeRAM) is a type of non-volatile computer memory, similar to EEPROM but based on electric field orientation and with near-unlimited number (exceeding 1010 for 5V devices and even more for 3. ... Magnetoresistive Random Access Memory (MRAM) is a non-volatile computer memory (NVRAM) technology, which has been in development since the 1990s. ...


Comparison with EPROM and EEPROM/Flash

The difference between EPROM and EEPROM lies in the way that the memory programs and erases. EEPROM can be programmed and erased electrically using field emission (more commonly known in the industry as "Fowler-Nordheim tunneling"). EPROM. The small quartz window admits UV light during erasure. ... Field emission, also known as Fowler-Nordheim tunneling, is a form of quantum tunneling in which electrons pass through a barrier in the presence of a high electric field. ...


EPROMs can't be erased electrically, and are programmed via hot carrier injection onto the floating gate. Erase is via an ultraviolet light source, although in practice many EPROMs are encapsulated in plastic that is opaque to UV light, and are "one-time programmable". This article or section is in need of attention from an expert on the subject. ... For other uses, see Ultraviolet (disambiguation). ...


Most NOR Flash memory is a hybrid style—programming is through Hot carrier injection and erase is through Fowler-Nordheim tunneling. A USB flash drive. ... This article or section is in need of attention from an expert on the subject. ...


EEPROM manufacturers

Atmel ATMEGA32 microcontroller Atmel AT90S2333 microcontroller Atmel Corporation (NASDAQ: ATML) is a manufacturer of semiconductors, founded in 1984. ... It has been suggested that Hitachi Works be merged into this article or section. ... Infineon Technologies is a German manufacturer of integrated circuits and related products. ... Maxwell Technologies - headquarters, San Diego, USA Supercapacitors MC2600 series (with capacitance 2600 farads) produced by Maxwell Technologies Maxwell Technologies - developer and manufacturer of energy storage and power delivery solutions. ... Microchip Technology (NASDAQ: MCHP) is a manufacturer of semiconductors, founded in ??. Its products include microcontrollers (PICmicro, dsPIC, PIC24), EEPROM and Flash memory devices, KEELOQ devices, radio frequency (RF) devices, battery management devices, interface devices, analog devices and many others. ... For other uses of NXP, see NXP (disambiguation). ... Renesas Technology Corporation ) is a Japanese semiconductor manufacturer. ... Samsung Electronics (SEC, Hangul:삼성전자; KRXS: 005930, KRXS: 005935, LSE: SMSN, LSE: SMSD) is the worlds largest electronics and information technology company[1], headquartered in Suwon, South Korea. ... STMicroelectronics is an international leading supplier of semiconductors. ... Seiko Instruments Inc. ... Winbond Electronics Corporation is a Taiwan-based corporation which was founded in 1987 and is a producer of semiconductors and several types of integrated circuits, most notably Dynamic RAM, Static RAM and microcontrollers. ...

See also

It has been suggested that this article or section be merged with Non-volatile memory. ... A USB flash drive. ... DataFlash is a low pin-count serial interface for flash memory. ...

References

  1. ^ Rostky, George (July 2, 2002). "Remembering the PROM knights of Intel". EE Times. Retrieved on [[February 8, 2007]]. 
  2. ^ System Integration - From Transistor Design to Large Scale Integrated Circuits
is the 39th day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ...

  Results from FactBites:
 
EEPROM Definition: TechEncyclopedia from TechWeb (471 words)
EEPROMs use a transistor with a floating gate underneath a control gate.
EEPROMs have a lifespan of between 10K and 100K write cycles, which is considerably greater than the EPROMs (single "E") that preceded them.
A single EEPROM bit is made up of two transistors: the MOS transistor for erasure and the floating gate transistor for storage.
EEPROM - Wikipedia, the free encyclopedia (596 words)
Serial EEPROMs come in a range of capacities from a few bytes to over 128 kilobytes and are typically used to store configuration parameters, and in modern computers they replace the hitherto CMOS nonvolatile BIOS memory.
Also, RAM is generally a lot faster to write than EEPROM (typically a few nanoseconds as opposed to a few microseconds), and most types of RAM are volatile (they lose their contents when power is removed).
EEPROM takes more die area than flash memory for the same capacity because each cell usually needs both a read, write and erase transistor where in flash memory the erase circuits are shared by blocks of many (often 512×8) cells.
  More results at FactBites »

 
 

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