Microchip Technology AT28C256F-15SU

Overview

AT28C256F-15SU from Microchip Technology is an industrial-grade paged parallel EEPROM with 256-Kbit (32,768 × 8) organization, 150 ns read access time, 3 ms maximum page write cycle, 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 in programmable logic controllers and legacy industrial interfaces.

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

Technical Context

The AT28C256F-15SU implements a paged architecture with a 64-byte internal page register, enabling simultaneous latching of up to 64 bytes before autonomous internal programming. Its dual-line chip enable (CE) and output enable (OE) control allows bus contention avoidance in shared-memory systems.

Write operations are validated via DATA polling on I/O7 (complement-to-data during write, true data upon completion) or toggle-bit monitoring on I/O6. Hardware protection includes VCC sense (<3.8 V inhibits writes), 5 ms power-on delay, and noise filtering on WE/CE inputs (rejects <15 ns pulses).

Key Specifications

Pinout & Package

AT28C256F-15SU is supplied in a 28-lead SOIC package (JEDEC MS-012) with 0.300-inch body width and gull-wing leads. Pin 1 is marked by a beveled corner or notch; package conforms to JEDEC byte-wide pinout standard.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT28C256-15SU, the AT28C256F-15SU delivers 70% faster page writes for reduced system update windows, while AT28C256E-15SU adds 10× endurance for high-cycle calibration storage-both retain identical JEDEC pinout, 150 ns read timing, and software/hardware protection features.

Availability

AT28C256F-15SU is available at Aetrix Electronics and suitable for industrial control systems, legacy bus interface adapters, programmable logic controllers, and human-machine interface displays requiring stable component supply and long-term obsolescence management.

Supply support for AT28C256F-15SU 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 for industrial, automotive, and consumer applications.

The AT28C256 family was designed to provide pin-compatible, low-power, high-reliability EEPROM alternatives to EPROM and battery-backed SRAM in legacy embedded systems requiring field-upgradable configuration and firmware storage.

FAQ

What is the maximum page write time for AT28C256F-15SU?

The AT28C256F-15SU has a maximum page write cycle time of 3 ms, confirmed in Table 6-4 of the DS20006386B datasheet. This is the defining "F" variant characteristic distinguishing it from the standard 10 ms AT28C256-15SU and the extended-endurance AT28C256E-15SU. The 3 ms specification applies to all 1–64 byte page writes under industrial temperature and 5V ±10% supply conditions.

Does AT28C256F-15SU support both hardware and software data protection?

Yes, AT28C256F-15SU implements dual-layer data protection: hardware features include VCC sense (write inhibition below 3.8 V), 5 ms power-on delay, WE/CE noise filtering, and write-inhibit logic; software protection uses a three-step command sequence (AAh/55h/A0h) to enable/disable write lock. Both mechanisms operate independently and are fully documented in Sections 6.11–6.12 of the AT28C256F-15SU datasheet.

Which pins are used for write completion detection on AT28C256F-15SU?

AT28C256F-15SU supports two write completion detection methods: DATA polling monitors I/O7 (outputs complement of last written byte until write completes, then true data), and toggle-bit detection monitors I/O6 (toggles between 0 and 1 during write, stabilizes upon completion). Both functions are active simultaneously and require no additional hardware-details are in Sections 6.14 and 6.16 of the AT28C256F-15SU datasheet.

What package type is used for AT28C256F-15SU?

AT28C256F-15SU is packaged in a 28-lead Small Outline Integrated Circuit (SOIC) with 0.300-inch body width (JEDEC MS-012). The "SU" suffix explicitly denotes this SOIC package, distinct from the "PU" (PDIP) and "LU" (PLCC) variants. Pin 1 is identified by a beveled corner or notch per Microchip's packaging specification DS20006386B-page 21.

Is AT28C256F-15SU compatible with standard 5V TTL and CMOS logic levels?

Yes, AT28C256F-15SU features CMOS and TTL compatible inputs and outputs per Section 1 of the datasheet. Input thresholds meet TTL (VIL ≤ 0.8 V, VIH ≥ 2.0 V) and CMOS (VIH ≥ 70% VCC) standards; output drive strength supports VOH ≥ 2.4 V at –400 µA and VOL ≤ 0.45 V at 2.1 mA-enabling direct interfacing with legacy 8051, Z80, and 68K-based systems without level-shifting circuitry.