Microchip Technology AT28C256E-15JU

Overview

AT28C256E-15JU from Microchip Technology is an industrial-grade 256-Kbit paged parallel EEPROM organized as 32,768 × 8, featuring 150 ns read access time, 10 ms maximum page write cycle time, and 100,000 write endurance cycles. It operates from a single 5V ±10% supply, supports JEDEC-standard byte-wide pinout, and delivers 200 µA CMOS standby current for low-power embedded memory applications.

For engineers reviewing the AT28C256E-15JU datasheet, AT28C256E-15JU pinout, AT28C256E-15JU application, or AT28C256E-15JU equivalent, this device serves as a drop-in replacement for legacy parallel EEPROMs in firmware storage, configuration retention, and boot code storage where deterministic timing, hardware/software data protection, and industrial temperature operation (–40°C to +85°C) are required.

Technical Context

The AT28C256E-15JU implements a paged write architecture with a 64-byte internal page register, enabling 1–64 byte writes per internal programming cycle. Its dual-line chip enable (CE) and output enable (OE) control logic allows flexible bus contention management during read operations.

It integrates VCC sense, power-on delay, noise filtering, and software data protection (SDP) to prevent inadvertent writes. Data polling on I/O7 and toggle-bit detection on I/O6 provide deterministic end-of-write signaling without requiring external timers or status registers.

Key Specifications

Pinout & Package

AT28C256E-15JU is supplied in a 32-lead PLCC (Plastic Leaded Chip Carrier) package with JEDEC-standard byte-wide pinout and no internal connection to pins 1 (DC) and 12 (NC). The package features gull-wing leads, 1.27 mm pitch, and conforms to JEDEC MS-016 Variation AE.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar paged parallel EEPROM applications.

Compared with AT28C256-15PU and AT28C256-15SU, the AT28C256E-15JU offers superior mechanical reliability and thermal performance in industrial environments due to its 32-lead PLCC construction, while maintaining identical functional behavior and pin-level compatibility across all three variants.

Availability

AT28C256E-15JU is available at Aetrix Electronics and suitable for industrial control systems, medical instrumentation, and telecommunications infrastructure requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature operation.

Supply support for AT28C256E-15JU includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Microchip Technology is a global semiconductor company specializing in microcontrollers, analog devices, and nonvolatile memory solutions, with a focus on industrial, automotive, and aerospace applications.

The AT28C256 product line delivers high-reliability, paged parallel EEPROMs designed for firmware storage, configuration retention, and boot code hosting in legacy and upgrade systems where deterministic timing and industrial-grade endurance are essential.

FAQ

What is the maximum page write size supported by the AT28C256E-15JU?

The AT28C256E-15JU supports up to 64 bytes per page write operation. This is enabled by its internal 64-byte page register, which latches address and data during a single write initiation. All bytes written in one page cycle must reside within the same 64-byte boundary defined by address bits A6–A14. The AT28C256E-15JU requires each successive byte to be loaded within 150 µs of the previous one to maintain page mode operation.

How does the AT28C256E-15JU indicate completion of a write cycle?

The AT28C256E-15JU provides two hardware-supported methods: DATA Polling on I/O7 and Toggle Bit detection on I/O6. During a write, reading the last written byte returns the complement of the data on I/O7; when the write completes, true data appears. Alternatively, I/O6 toggles between 0 and 1 during the write and stabilizes upon completion. Both mechanisms allow the host to detect write finish without fixed delays or external components - a key feature of the AT28C256E-15JU.

Is the AT28C256E-15JU pin-compatible with older 27C256 EPROMs?

The AT28C256E-15JU uses a JEDEC-approved byte-wide pinout identical to the 27C256 EPROM in 28-pin packages, but the AT28C256E-15JU is supplied in a 32-pin PLCC. While the core signal mapping (A0–A14, I/O0–I/O7, CE, OE, WE, VCC, GND) matches, the AT28C256E-15JU includes two additional NC pins (1 and 12) and omits the 27C256's PGM pin. Direct socket replacement requires adapter or PCB redesign - however, the AT28C256E-15JU maintains functional equivalence and timing compatibility.

What write endurance rating does the 'E' suffix denote in AT28C256E-15JU?

The 'E' suffix in AT28C256E-15JU indicates Extended endurance: 100,000 write/erase cycles at the 10 ms page write specification. This contrasts with the standard 'blank' version (10,000 cycles) and the 'F' variant (10,000 cycles at 3 ms). The AT28C256E-15JU's 100K-cycle rating is validated under industrial temperature conditions and supports long-life deployments in programmable logic controllers and test equipment where frequent configuration updates occur.

Does the AT28C256E-15JU require a 12V supply for any operation?

The AT28C256E-15JU operates from a single 5V ±10% supply for all standard read and write functions. A 12V ±0.5V supply on pin A9 is required only for accessing the optional 64-byte device identification area (7FC0h–7FFFh) or executing the software chip erase command. These 12V operations are strictly optional and not needed for normal firmware or configuration storage - the AT28C256E-15JU functions fully at 5V in all standard use cases.