Microchip Technology AT28C256F-15TU-T

Overview

AT28C256F-15TU-T from Microchip Technology is an industrial-grade 256-Kbit paged parallel EEPROM organized as 32,768 × 8, featuring 150 ns read access time, 3 ms maximum page write cycle time, and single 5V ±10% supply operation. It supports hardware/software data protection, DATA polling, and toggle-bit write completion detection for embedded control and firmware storage applications.

For engineers reviewing the AT28C256F-15TU-T datasheet, AT28C256F-15TU-T pinout, AT28C256F-15TU-T application, or AT28C256F-15TU-T equivalent, key selection considerations include JEDEC byte-wide pin compatibility, 3 ms fast page write timing, industrial temperature range (–40°C to +85°C), CMOS/TTL I/O compatibility, and software data protection enable/disable algorithms.

Technical Context

The AT28C256F-15TU-T implements a paged write architecture with a 64-byte internal latching register, enabling up to 64-byte writes within a single internal programming period. Its dual-line chip enable (CE) and output enable (OE) control allows flexible bus contention management during read operations.

Write completion is verified via DATA polling on I/O7 (complement-to-data during write, true data after completion) or toggle-bit behavior on I/O6. Hardware protection includes VCC sense (<3.8V inhibit), 5 ms power-on delay, and noise filtering on WE/CE inputs (15 ns pulse rejection).

Key Specifications

Pinout & Package

AT28C256F-15TU-T is supplied in a 28-lead SOIC package with JEDEC-standard byte-wide pinout. The package features gull-wing leads, 1.27 mm pitch, and conforms to JEDEC MS-012AB.

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 AT28C256F-15TU-T delivers faster 3 ms page writes in a surface-mount SOIC package, making it optimal for space-constrained industrial designs requiring rapid field updates without sacrificing JEDEC compatibility or industrial temperature support.

Availability

AT28C256F-15TU-T is available at Aetrix Electronics and suitable for industrial PLC configuration storage, legacy embedded system firmware backup, and automotive body control module NVM requiring stable component supply across extended product lifecycles.

Supply support for AT28C256F-15TU-T 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 components, and nonvolatile memory solutions with a focus on industrial, automotive, and communications markets.

The AT28C256 family was designed for byte-wide parallel interface applications requiring reliable, low-power, and pin-compatible EEPROM replacement in legacy 5V systems with strict timing and endurance requirements.

FAQ

What is the maximum page write size supported by the AT28C256F-15TU-T?

The AT28C256F-15TU-T supports up to 64 bytes per page write operation. This is enabled by its internal 64-byte latching register, which allows sequential data loading within a 150 µs window between bytes. All addresses written in a single page operation must reside on the same page, defined by A6–A14; A0–A5 select individual bytes within that page. This capability reduces firmware update overhead compared to byte-by-byte writes.

Does the AT28C256F-15TU-T require external circuitry for write protection during power-up?

No, the AT28C256F-15TU-T includes built-in hardware write protection that activates automatically during power transitions. It features VCC sensing (write inhibited below ~3.8V), a 5 ms internal power-on delay timer, and noise filtering on WE/CE inputs (rejecting pulses <15 ns). These functions eliminate the need for external reset supervisors or RC networks, simplifying design and improving reliability in 5V systems.

How is write completion detected on the AT28C256F-15TU-T?

Write completion on the AT28C256F-15TU-T can be detected using either DATA polling on I/O7 or the toggle-bit method on I/O6. During a write, reading the last written address returns the complement of the data on I/O7; when true data appears, the write is complete. Alternatively, I/O6 toggles between 0 and 1 during the write and stabilizes once finished. Both methods allow real-time status monitoring without external timing components.

What is the difference between the 'F' and standard suffix in AT28C256 part numbers?

The 'F' suffix in AT28C256F-15TU-T denotes the Fast Write variant, specifying a maximum page write cycle time of 3 ms (vs. 10 ms for standard AT28C256-15xx parts). This is achieved through process and timing optimizations in Microchip's manufacturing. Electrical specifications, pinout, voltage, temperature range, and software data protection functionality remain identical - only the internal programming speed differs.

Is the AT28C256F-15TU-T compatible with existing AT28C256-15PU designs?

Yes, the AT28C256F-15TU-T is pin-compatible and functionally equivalent to the AT28C256-15PU in all electrical and timing parameters except page write speed. Both share identical 28-pin SOIC/PDIP footprints (JEDEC MS-012AB), 5V supply, 150 ns read access, and software data protection algorithms. Replacing the PDIP version with the SOIC AT28C256F-15TU-T requires no schematic or firmware changes - only PCB layout adaptation for surface-mount assembly.