Donor challenge: Your generous donation will be matched 2-to-1 right now. Your $5 becomes $15! Dear Internet Archive Supporter,. I ask only. Details, datasheet, quote on part number: DESCRIPTION The a 65, bit UV erasable and electrically programmable memory EPROM. It is organized. High speed performance. – ns access time available. • CMOS Technology for low power consumption. – 20 mA Active current. – µA Standby current.

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As the quartz window is expensive to make, OTP one-time programmable chips were introduced; here, the eporm is mounted in an opaque package so it cannot be erased after programming — this also eliminates the need to test the erase function, datasheeet reducing cost. 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.

It is an array of floating-gate transistors individually programmed by eprpm electronic device that supplies higher voltages than those normally used in digital circuits. To retrieve data from the EPROM, the address represented by the values at the address pins of the EPROM is decoded and used to connect one word usually an 8-bit byte of storage to the output buffer amplifiers. It’s almost completely unreadable. For example, one manufacturer might use 21vpp for their ICs whereas another may use 25vpp.

This creates an avalanche dahasheet of electrons, which have enough energy to pass through the insulating oxide layer and accumulate on the gate electrode.


2764A – 2764A 64K EPROM Datasheet

However, as this was not universal, programmer software also would allow manual setting of the manufacturer and device type of the chip to ensure proper programming. When the high voltage is removed, the electrons are trapped on the electrode.

A control gate electrode is deposited and further oxide covers it.

Modern programmers use menu-based interfaces that are easy to use. A programmed EPROM datasjeet 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. First rule is to know the kind of EPROMS you want or are likely to want to burn satasheet get a programmer that can handle them.

EPROM – Wikipedia

Presence of a voltage on this 7264 creates a conductive channel in the transistor, switching it on. Since the whole memory array is exposed, all the memory is erased at the same time. Even dust inside the package can prevent some cells from being erased. Don’t look directly at the bulb when the door is open. Wprom field-effect transistor consists of a channel in the semiconductor body of the device. Retrieved from ” https: Make sure you know the specs you’re dealing with. Cambridge University Press, p.

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.

From time to time those of us with the passion to preserve ancient computers from the and s will come across the need to replace a failed masked ROM or EPROM.


If things are OK, you’re done.

EPROM programming is slow compared to other forms of memory. It may even check automatically. Otherwise there is great risk of zapping the ROM because voltage is applied to the wrong pin!

IC Datasheet: 2764 EPROM

Digital Design and Fabrication. Not all ROM images are available on the Web and it’s a good idea to extract the code for posterity and possible future use! Shining ultraviolet light on any part of an unpackaged device causes a photocurrent to flow from the floating gate back to the silicon substrate, thereby discharging datasheey gate to its initial, uncharged condition photoelectric effect.

While parts of the same size from different manufacturers are compatible in epgom mode, different manufacturers added different and sometimes multiple programming modes leading to subtle differences in the programming process.

The erasing window must be kept covered with an opaque label datzsheet prevent accidental erasure by the UV found in sunlight or camera flashes. It is not the harmless UV found in disco lights. Initially, it was thought that the EPROM would be too expensive for mass production use and that it would be confined to development only.

To erase the data stored in the array of transistors, ultraviolet light is directed onto the die. Be sure to check when ordering and make sure you get the UV-erasable version unless you want an OTP of course.

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