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This section provides an overview for electrically programmable read-only (eprom) memory as well as their applications and principles. Also, please take a look at the list of 6 electrically programmable read-only (eprom) memory manufacturers and their company rankings. Here are the top-ranked electrically programmable read-only (eprom) memory companies as of December, 2024: 1.Microchip Technology Inc., 2.ABLIC Inc., 3.Renesas Electronics Corporation..
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EPROM stands for "erasable programmable read-only memory" and is a semiconductor memory that can write and erase data a certain number of times.
EPROM is a nonvolatile memory that retains the content of written data even when the power is turned off. EPROM erases all data in the memory by exposing it to strong ultraviolet light for a certain period of time.
Therefore, it is not possible to erase the data, leaving only a portion of the data. In addition, it should be noted that continuous exposure to sunlight or fluorescent light over a long period of time will erase the data. Because the data can be rewritten only a few dozen times or because it takes a certain amount of time to erase data, EEPROM (electrically erasable PROMs) and flash memory, which use electricity to erase data, have been replacing EPROM in recent years.
EPROMs are used in computer-controlled equipment where programs and data are written to them. They can erase and write data many times but must be subjected to a UV irradiation device in order to erase the data.
When embedded in electronic equipment, EPROMs must be removed from the equipment and subjected to UV irradiation each time data is rewritten. For this reason, EEPROMs, which can rewrite data electrically, are becoming the mainstream.
In EPROMs, one bit of data is held in a single transistor. The transistor that holds the data is called a memory cell transistor.
The memory cell transistor in EPROMs has an electrically isolated floating gate embedded in the gate oxide film.
EPROMs consist of a grid of memory cells.
The principles of EPROMs are explained from three perspectives.
By applying a high voltage to the control gate of a memory cell transistor, electrons flowing between the source and drain in the memory cell transistor channel acquire high energy. Some of the energized electrons jump over the gate oxide film and are injected into the floating gate, causing the gate to become negatively charged. When the floating gate becomes negatively charged, data has been recorded.
The voltage applied to the control gate for the transistor to function is called the threshold voltage. A memory cell transistor in which data has been written and the floating gate is negatively charged must have a higher threshold voltage applied to the control gate than a memory cell transistor in which no data has been written to operate.
The voltage between the threshold voltage of the memory cell transistor to which no data has been written and the threshold voltage of the memory cell transistor to which data has been written is called the read voltage. The presence or absence of data can be determined by whether the memory cell transistor turns on or off when the read voltage is applied.
Irradiation with ultraviolet light causes the electrons in the floating gate to enter a high-energy state. The energized electrons jump over the gate oxide film and are released into the substrate and control gate. The floating gate that has released the electrons becomes electrically neutral, and the threshold voltage of the memory cell transistor returns to its initial value.
The reason why EPROMs erase all data at once is because it is difficult to focus the ultraviolet irradiation on a specific memory cell transistor.
EPROM memory capacities range from 2 kilobits (256 bytes) to 32 megabits (4 megabytes). The number after 27 in the model number is the memory capacity.
For example, 2732 indicates a 32-kilobit capacity, while 2764 indicates a 64-kilobit capacity. In addition, those with a C after 27 in the model number, such as 27C32 and 27C64, indicate that the memory cell transistor has a CMOS structure.
*Including some distributors, etc.
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Microchip Technology Incorporated was incorporated in 1989 and is headquartered in Chandler, Arizona. The company is a developer and manufacturer of control solutions for global markets including the automotive, industrial, communications, human-machine interface, and connectivity industries. The company’s products include microcontrollers, field-programmable gate array products, MOSFET and radio frequency products, and both wired and wireless communications products. The company’s services include wafer foundry and assembly services, test subcontracting manufacturing services, development tools for enabling system designers to program microcontrollers and processors, and timing system products.
Rochester Electronics, LLC is a manufacturer stocking distributor of end-of-life semiconductors and the broadest range of active semiconductors that is headquartered in Newburyport, Massachusetts, and was founded in 1981. The company caters to manufacturing services ranging from design, wafer processing, testing, reliability, and IP Archiving. These specifically include OCM, build-to-order products, process flows, and standard packaging creation. The company pivots on manufacturing and distributing semiconductors that are no longer produced by its original manufacturer.
Renesas Electronics Corporation was established in 2002 and is headquartered in Tokyo, Japan. Renesas is a global research, design, and manufacturer of semiconductors used in industries spanning automotive, consumer electronics, the internet of things, power & energy, and industrial sectors. Renesas manufactures both analog and digital products. Analog products include amplifiers, audio & video devices, data converters, PLC, and switches & multiplexers. Digital products include microcontrollers, memory components, sensors, wireless connectivity products, and others. Renesas also offers design resources such as kits, development tools, partner programs, and design tools.
Twilight Technology, Inc., established in 1996 and headquartered in Anaheim, USA, is a manufacturer of IC packaging and testing services. The company specializes in footprint conversions, RoHS compliance, and custom packaging and provides solutions for the military, aerospace, and commercial sectors. Its capabilities include nitrogen die banking and obsolescence management, ensuring continued support for components facing limited availability. The company also offers standard and custom replacements for obsolete semiconductors, utilizing original or compatible die to maintain form, fit, and function. It offers prototyping and manufacturing services and employs cutting-edge technology and CAD software in its products.
ABLIC, Inc. is a manufacturer of analog semiconductors and integrated circuits (ICs) based in Minato-ku, Tokyo. Originally established in 2016, the company is a subsidiary of Seiko Instruments, Inc., and was renamed SII Semiconductor Corporation in 2018. The company produces memory, logic, and power management ICs, as well as various sensors for use in mobile computers, industrial equipment, wearable tech, and automotive systems. These supply clients in the consumer electronics, factory automation, and medical equipment industries.
ST Micro Electronics is a global semiconductor company serving customers with innovations to have a positive impact on people's lives. Their product line is micro electronic systems, such as switches, controllers, sensors and drivers. The main selling point of ST Micro Electronics is its provision of sustainable products, and introducing their electronics to create a more sustainable world. The company, as well as providing the electronic devices, also provides software and support, ensuring that all fields are covered to provide a fully provide a supported and strong relationship with their customer base. ST Micro Electronics believe that technology plays a key role in helping to solve environmental and social challenges, which is why their semiconductor technologies start with their employees, their customers and partners.
Ranking as of December 2024
Derivation Method| Rank | Company | Click Share |
|---|---|---|
| 1 | Microchip Technology Inc. |
60.0%
|
| 2 | ABLIC Inc. |
20.0%
|
| 3 | Renesas Electronics Corporation. |
20.0%
|
Derivation Method
The ranking is calculated based on the click share within the electrically programmable read-only (eprom) memory page as of December 2024. Click share is defined as the total number of clicks for all companies during the period divided by the number of clicks for each company.Number of Employees
Newly Established Company
Company with a History
*Including some distributors, etc.
*Including some distributors, etc.
| Country | Number of Companies | Share (%) |
|---|---|---|
|
United States of America
|
2 | 66.7% |
|
Japan
|
1 | 33.3% |
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