Intel DT28F320S5-90 32Mbit (4MB) Boot Block Flash Memory Chip Technical Overview

The Intel DT28F320S5-90 is a 32-megabit (4-megabyte) flash memory chip engineered for a specific and critical role: storing firmware and boot code in embedded systems. Manufactured using Intel's advanced flash technology, this component is distinguished by its Boot Block architecture, a feature that provides robust data protection for essential system startup code.

This device is organized as a 4M x 8-bit memory array, meaning it handles data in byte-wide chunks, which simplifies interfacing with common 8-bit and 16-bit microprocessors and microcontrollers. Its single 5-volt power supply requirement makes it highly suitable for a wide range of computing applications without the need for complex voltage level shifting.

A key characteristic of the DT28F320S5-90 is its 90ns maximum access time. This speed is critical for systems where the CPU must execute code directly from the flash memory (XIP - Execute-In-Place) without significant performance bottlenecks, especially during the initial boot process.

The most defining feature of this chip is its asymmetrically blocked architecture. The 32Mbit array is divided into multiple blocks, but one or more of these are designated as hardware-locked boot blocks. These specific blocks, typically located at the top or bottom of the memory map, can be permanently or temporarily protected from accidental erasure or programming through a hardware-driven locking mechanism. This ensures the integrity of the vital boot code, even if other sections of the memory are updated or become corrupted.

The chip supports a standard JEDEC-approved command set for common flash interface (CFI), allowing for simplified programming and erasure through a series of software commands. Entire chip or individual block erase operations are managed through this protocol. The DT28F320S5-90 is designed for high reliability and endurance, capable of supporting a minimum of 100,000 program/erase cycles per block.

Its primary applications are found in areas where reliable booting is non-negotiable, including networking equipment (routers, switches), telecommunications infrastructure, industrial control systems, and modern automotive electronics.

ICGOODFIND: The Intel DT28F320S5-90 is a specialized flash memory solution prized for its robust boot code protection via hardware-locked sectors, fast 90ns access time for efficient system startup, and industry-standard 5V operation, making it a reliable choice for critical embedded firmware storage.

Keywords: Boot Block Flash, 32Mbit Memory, Hardware Locking, 90ns Access Time, Firmware Storage.