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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The effects of this process on the reliability of the part would have required extensive testing so they decided on the window instead.

It is dagasheet the harmless UV found in disco lights. Retrieved from ” https: It’s also inexpensive, is completely software driven and can supply all necessary programming voltages from a USB link. Exposure time for sunlight of one week or three years for room fluorescent lighting may cause erasure. First rule is to know the kind of EPROMS you want or are likely to want to burn and get a programmer that can handle them.

The other voltage is the programming voltage Vpp. Magnetic tape Hard disk drive.

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! In effect, the stored charge on the floating gate allows the threshold voltage of the transistor to be programmed.

Archived PDF from the original on To erase the data stored in the array of transistors, ultraviolet light is directed onto the die.

EPROM programming is slow compared to other forms of memory. Here is an important piece of advice. Each bit of the word is a 1 or 0, depending on the storage transistor being switched on or off, conducting or non-conducting. Be sure to check when ordering and make sure you get the UV-erasable version unless dataheet want an OTP of course.

Try 20 minutes first and if that doesn’t fully erase the chip try again dataheet a longer interval until you find a time span that does. This page was last edited on 8 Novemberat After the prefix is a number such as 16, or 32, 64, etc.


Here is one of my efforts regarding the latter. There will be an icon or menu selection for this. Once programmed, an EPROM can be erased by exposing it to strong ultraviolet light source such as from a mercury-vapor light.

2764A – 2764A 64K EPROM Datasheet

Often the pin-outs of the mask ROM will be different to the EPROM and some kind of “adapter” needs to be made to switch the pins around or the board circuitry altered. When the high voltage is removed, the electrons are trapped on the electrode. This creates an avalanche discharge of electrons, which have enough energy to pass through the insulating oxide layer and accumulate on the gate electrode.

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 the gate to its initial, uncharged condition photoelectric effect.

EPROMS: The minimum you need to know to burn your own

Erasure, however, has to be accomplished by non-electrical methods, since the gate electrode is not accessible electrically. 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. For large volumes of parts thousands of pieces or moremask-programmed ROMs are the lowest cost devices to produce.

The incorrect voltage can kill it. From Wikipedia, the free encyclopedia. In other projects Wikimedia Commons. To eprlm data from the EPROM, the address satasheet 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.

However the programming devices mentioned below do handle these other chips. While parts of the same size from different manufacturers are compatible in read mode, different manufacturers added different and sometimes multiple programming modes leading to subtle differences in the programming process.

Mask ROMS datqsheet embedded code that can’t be changed. A couple of VCF folks datashert me refine this article. A control gate electrode is deposited and further oxide covers it.


Initially, it was thought that the EPROM would be too expensive for mass production use and that it would be confined to development only. Usually these ICs start with either a or a prefix but there may be others. If you know the basics though the software is easy enough to follow.

There are epro number of programmers on the market. The switching state of the field-effect transistor is controlled by the voltage on the control gate of the transistor. The erasing window must be kept covered with an opaque label to prevent accidental erasure by the UV found in sunlight or camera flashes.

For example, one manufacturer might use 21vpp for their ICs whereas another may use 25vpp. Source and drain contacts are made to regions at the end of the channel. Each field-effect transistor consists of a channel in the semiconductor body of the device. Cambridge University Press, p. The ICs hold code, often an auxiliary program such as an application, utility or game which can be loaded immediately on startup.

IC Datasheet: 2764 EPROM

It was soon found that small-volume production was economical with EPROM parts, particularly when the advantage of rapid upgrades of firmware was considered. It seems to work well, although at the time of writing the manual for this Chinese device appears to have been written using an early version of Google Translator! 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.

For your average vintage microcomputer, EPROMS can be recognised by their clear transparent windows, normally covered by some kind of label.

The recommended erasure procedure is exposure to UV light at Figure 4 shows a screen shot of my programmer with a 4k System 80 ROM image loaded.