(EPROM). The device is organized into 64K words by. 8 bits (64K bytes). Accessing individual bytes from an address transition or from power-up (chip enable. DESCRIPTION. The M is a , bit UV erasable and electrically programmable memory EPROM. It is organized as 65, words by 8 bits. MF1 STMicroelectronics EEPROM DISC BY SGS 11/95 datasheet, inventory, & pricing.

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This prompted larger capacity devices to introduce a “signature mode”, allowing the manufacturer and device to be identified by the EPROM programmer.

27512 EPROM

This creates an avalanche discharge of electrons, which have enough energy to pass through the insulating oxide layer and accumulate on the gate electrode. The erasing window must be kept covered with an opaque label to prevent accidental erasure by the UV found in sunlight or camera flashes.

Storing data in the memory requires selecting a given address and applying a higher voltage to the transistors. In other projects Wikimedia Commons. While parts of the same size from different manufacturers are compatible in read mode, different manufacturers added eepfom and sometimes multiple programming modes leading to subtle differences in the programming process. Initially, it was thought that the EPROM would be too expensive for mass production use and that it would be confined eeproom development only.

It is an array of floating-gate efprom individually programmed by an electronic device that supplies higher voltages than those normally used in digital circuits. Eelrom of the EPROM memory cell started with investigation of faulty integrated circuits where the gate connections of transistors had broken. International Trade Commission, ed. Cambridge University Press, p.

ST Microelectronics – datasheet pdf

The switching state of the field-effect transistor is controlled by the voltage on the control gate of the transistor. Each field-effect transistor consists of 227512 channel in the semiconductor body of the device.


EPROM programming is slow compared to other forms of memory. Source and drain contacts are made to regions at the end of the channel. Photons of 227512 UV light cause ionization within the silicon oxide, which allow the stored charge on the floating gate to dissipate.

An insulating layer of oxide is grown over the channel, then a conductive silicon or aluminum gate electrode is deposited, and a further thick layer of oxide is deposited over the gate electrode. The first generation devices eeprm fabricated with the p-MOS techology. As the quartz window is expensive to make, OTP one-time programmable chips were introduced; here, the die eepprom mounted in an opaque package so it cannot be erased after programming — this also eliminates the need to test the erase function, further reducing cost.

ST Microelectronics

Shining ultraviolet light on any eeprlm of an unpackaged device causes a photocurrent to flow from the floating gate back to the silicon substrate, thereby discharging the gate to its initial, uncharged condition photoelectric effect.

Leaving the die of such a chip exposed to light can also change behavior eepron unexpected ways when moving from a windowed part used for development to a non-windowed part for production. A programmed EPROM retains its data for a minimum of ten to twenty years, [5] with many still retaining data after 35 or more years, and can be read an unlimited number of times without affecting the lifetime.

From Wikipedia, the free encyclopedia. Archived PDF from the original on Views Read Edit View history. This page was last edited on 8 Novemberat All articles with unsourced statements Articles with unsourced statements from October Commons category link from Wikidata Wikipedia articles with GND identifiers. However, these require eepom weeks lead time to make, since the artwork for an IC mask layer must be altered to store data on the ROMs. 2712


The recommended erasure procedure is exposure to UV light at The programming process is not electrically reversible. Computer memory that can retrieve stored data after a power supply has been turned off and back on is called non-volatile. Digital Design and Fabrication.

Magnetic tape Hard disk drive. When the high voltage is removed, the electrons are trapped on the electrode. Since the whole memory array is exposed, all the memory is erased at the same time. In effect, eeprim stored charge on the floating gate allows the threshold voltage of the transistor to be programmed.

Each bit of reprom word is a 1 or 0, depending on the storage transistor being switched on or off, conducting or non-conducting.

A control gate electrode is deposited and further oxide covers it. Presence of a voltage on this gate creates a conductive channel in the transistor, switching it on.

By using this site, you agree to the Terms of Use and Privacy Policy. In other words, to erase your EPROM, you would first have to X-ray it and then put it in an oven at about degrees Celsius to anneal semiconductor alterations caused by the X-rays.

It was soon found that small-volume production was economical with EPROM parts, particularly when the advantage of rapid upgrades of firmware was considered. The process takes several minutes for UV lamps of convenient sizes; sunlight would erase a chip in weeks, and indoor fluorescent lighting over several years. This method of erasure allows complete testing and correction of a complex eeprok array before the package is finally sealed.