Microchip Technology AT28BV256-20JC

Overview

AT28BV256-20JC from Atmel is a 256 Kbit (32K × 8) parallel EEPROM operating from a single 2.7V–3.6V supply, featuring 200 ns read access time, 10 ms maximum page write cycle, JEDEC-standard byte-wide pinout, and hardware/software data protection. It serves as nonvolatile program/data storage in microcontroller-based industrial control modules requiring battery-voltage operation and field-upgradable firmware.

For engineers reviewing the AT28BV256-20JC datasheet, AT28BV256-20JC pinout, AT28BV256-20JC application, or AT28BV256-20JC equivalent, key selection criteria include its 200 ns read timing, 64-byte page write capability, CMOS standby current of 20 µA, JEDEC-compliant PLCC-32 package, and dual data protection mechanisms for reliable embedded firmware retention.

Technical Context

The AT28BV256-20JC implements a parallel interface with CE/OE/WE control logic enabling SRAM-like read/write cycles without external timing circuitry. Its internal 64-byte page register latches address and data during page writes, decoupling bus activity from internal programming.

Write completion is verified via DATA polling on I/O7 or toggle-bit detection on I/O6, both usable at any point during the 10 ms internal write cycle. Hardware protection includes VCC power-on delay, noise filtering on WE/CE inputs, and write-inhibit states enforced by OE high, CE high, or WE high.

Key Specifications

Pinout & Package

AT28BV256-20JC is packaged in a 32-lead Plastic J-Leaded Chip Carrier (PLCC-32), JEDEC MS-016 compliant, with 1.27 mm pitch, 12.45 mm × 14.95 mm body, and lead coplanarity ≤0.102 mm. Pins 1 and 17 are designated "Don't Connect" per datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ST M28W256F and Microchip 25LC256, the AT28BV256-20JC uniquely balances 2.7V–3.6V operation, JEDEC pin compatibility, 200 ns speed, and dual hardware/software write protection-making it optimal for upgrading legacy 27C256-based systems without compromising reliability or timing.

Availability

AT28BV256-20JC is available at Aetrix Electronics and suitable for industrial PLC configuration storage, medical device calibration data retention, and automotive body control module firmware backup requiring stable component supply across extended temperature ranges.

Supply support for AT28BV256-20JC 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

Atmel Corporation (now part of Microchip Technology) is a fabless semiconductor company specializing in microcontrollers, nonvolatile memory, and secure authentication ICs for industrial, automotive, and consumer applications.

The AT28BV256 product line was designed specifically for battery-voltage parallel EEPROM replacement in legacy SRAM/EPROM-based systems, emphasizing low-power operation, JEDEC compatibility, and robust write protection for mission-critical firmware storage.

FAQ

What is the maximum page write size supported by the AT28BV256-20JC?

The AT28BV256-20JC supports a maximum page write size of 64 bytes. This is implemented via an internal 64-byte page register that latches address and data on the first write pulse, allowing subsequent bytes to be loaded within 150 µs intervals. All bytes in a single page write must reside on the same page defined by A6–A14 address lines, and the AT28BV256-20JC completes the internal programming automatically within 10 ms.

Does the AT28BV256-20JC require external high-voltage programming circuitry?

No, the AT28BV256-20JC operates from a single 2.7V–3.6V supply and does not require external high-voltage programming circuitry. All write operations-including byte and page writes-are executed using standard I/O voltage levels. The only exception is the optional 64-byte device identification area (7FC0H–7FFFH), which requires A9 raised to 12.0V ± 0.5V for access; this is strictly for ID memory and not used during normal AT28BV256-20JC operation.

How is write completion detected on the AT28BV256-20JC?

Write completion on the AT28BV256-20JC is detected using two hardware methods: DATA polling on I/O7 (which returns the complement of written data until completion) and the toggle-bit method on I/O6 (which toggles between 0 and 1 during programming and stabilizes upon completion). Both methods are usable at any time during the write cycle and eliminate the need for fixed timing delays. The AT28BV256-20JC specification guarantees these features function identically across all temperature and voltage conditions within its operating range.

What package type is used for the AT28BV256-20JC?

The AT28BV256-20JC uses a 32-lead Plastic J-Leaded Chip Carrier (PLCC-32) package, per JEDEC MS-016 Variation AE. Its dimensions are 12.45 mm × 14.95 mm with 1.27 mm lead pitch. Pins 1 and 17 are designated "Don't Connect" and must remain unconnected on the PCB. This package provides robust thermal performance and mechanical stability for industrial applications, and the AT28BV256-20JC's PLCC variant is pin-compatible with other members of the AT28BV256 family in the same package option.

Is the AT28BV256-20JC suitable for automotive applications?

The AT28BV256-20JC is rated for industrial temperature range (–40°C to +85°C) and meets key automotive subsystem requirements such as 2.7V–3.6V operation during cold-crank conditions and robust EMI immunity via hardware write-inhibit and noise-filtered WE/CE inputs. While not AEC-Q100 qualified, the AT28BV256-20JC has been widely deployed in automotive body control modules, infotainment configuration storage, and telematics firmware backup where extended temperature tolerance and proven field reliability are required. Its 10-year data retention and 10,000-cycle endurance align with typical automotive service life expectations.