Intel JS28F640J3D75: A Comprehensive Technical Overview of the 64-Megabit Flash Memory Chip
The Intel JS28F640J3D75 represents a significant component within the landscape of non-volatile memory solutions. As a 64-megabit (8-megabyte) NOR Flash memory chip fabricated on Intel's advanced 130nm process technology, it is engineered for high-performance, reliable code and data storage in a wide array of embedded systems. Its design prioritizes fast read access times, robust data integrity, and flexible in-system manageability, making it a cornerstone for applications ranging from telecommunications infrastructure and networking equipment to industrial control systems and automotive electronics.
Architecturally, the device is organized as 64 megabits, configured as 4,194,304 words by 16 bits or 8,388,608 words by 8 bits (via the BYTE pin). This word-wide organization is particularly advantageous for 16-bit microprocessor and microcontroller-based systems, enabling efficient direct code execution (Execute-In-Place, XIP) without the need to first shadow code into RAM. This capability is critical for systems requiring fast boot times and deterministic operation.
A key feature of this memory family is its 1.8V VCC core voltage supply, which significantly reduces power consumption compared to older 3.3V devices. This makes it suitable for power-sensitive and portable applications. The chip offers a page mode read capability, allowing for rapid burst reads from sequential locations, further enhancing system performance. For write operations, it supports a standard 12.0V VPP voltage for the programming and erase functions, which can be generated on-board or supplied externally.
The JS28F640J3D75 is built around a symmetric memory block architecture, dividing its total capacity into numerous individually erasable blocks. This granularity prevents the entire chip from being unavailable during a write or erase operation and allows specific sectors to be updated without disturbing others. The device fully supports the Common Flash Memory Interface (CFI), which enables host software to automatically query the chip to discover its architecture, electrical characteristics, and command set, simplifying system design and software portability.
Data integrity is paramount, and this Intel chip incorporates several advanced features to ensure it. It includes 64-bit protection registers for storing secure code or cryptographic keys, with hardware and software locking mechanisms to prevent unauthorized access or modification. Furthermore, it utilizes Error Correction Code (ECC) internally to detect and correct bit errors, greatly enhancing data retention and endurance over the product's lifespan, which is rated for a minimum of 100,000 write/erase cycles per block.
The "D75" suffix denotes a specific device speed grade, indicating a maximum initial access time of 75ns.
In-system management is handled through a sophisticated command sequencer, allowing all program and erase functions to be executed via a simple write sequence to the chip's internal command register. This abstracts the complex timing and voltage algorithms from the host processor, which simply polls status registers for operation completion.
ICGOOODFIND: The Intel JS28F640J3D75 is a highly integrated and reliable 64Mb NOR Flash memory solution. Its combination of a low-voltage core, fast read performance, advanced security features, and exceptional endurance solidifies its role as a trusted component for critical embedded systems requiring non-volatile storage.
Keywords: NOR Flash Memory, Execute-In-Place (XIP), Common Flash Interface (CFI), Error Correction Code (ECC), Block Erase Architecture.
