AT28C256EF-15JU

Memory IC Overview

The AT28C256EF-15JU is an industrial-grade, 256-Kbit (32,768 x 8) paged parallel EEPROM manufactured by Microchip Technology. It features a fast read access time of 150 ns and supports page write operations with a cycle time of 3 ms maximum. The device operates on a single 5V ± 10% supply, drawing 50 mA active current and less than 200 µA in CMOS standby mode. It includes hardware and software data protection mechanisms, such as VCC sense and Software Data Protection (SDP). The component is housed in a 32-lead PLCC package and is designed for applications requiring high reliability and non-volatile storage.

Memory IC Feature Summary

• Supports automatic page write operations allowing up to 64 bytes to be written simultaneously using internal address and data latches.
• Includes dedicated extra EEPROM memory space specifically allocated for device identification or tracking purposes.
• Provides dual detection methods for write cycle completion through DATA Polling on I/O7 and Toggle Bit functionality on I/O6.

Memory IC Applications

• Industrial control systems requiring robust non-volatile data retention
• Embedded devices needing secure configuration storage with hardware protection
• Automotive electronics utilizing high-reliability CMOS technology

Memory IC Procurement Notes

Verify the specific suffix 'E' indicates extended endurance and 'F' denotes fast write cycle characteristics when sourcing replacements. Confirm the 'J' suffix corresponds to the 32-lead PLCC package type. Ensure the 'U' suffix aligns with RoHS compliance requirements for your assembly process. Cross-reference the datasheet revision history to confirm pinout compatibility with existing designs.

Memory IC Selection Notes

Select this component for designs requiring a 3 ms page write cycle time rather than the standard 10 ms duration found in other variants. The extended endurance rating makes it suitable for frequent update cycles compared to standard endurance parts. Consider the 32-lead PLCC package constraints for PCB layout and thermal management. Verify that the host system can support the required 5V supply voltage and interface timing specifications.

Memory IC Part Context

This part belongs to the AT28C256 series of parallel EEPROMs from Microchip Technology. It shares the same core memory architecture and pinout as other AT28C256 variants but differs in performance characteristics defined by its ordering suffixes. The series is widely used in legacy and modern embedded systems where byte-wide parallel access is preferred over serial interfaces.

Memory IC Replacement Considerations

AT28C256E-15JU

Memory IC FAQ

How does the Software Data Protection (SDP) feature function?

SDP prevents inadvertent writes by requiring a specific three-byte command sequence before any write operation can occur. Once enabled, the device remains protected until the disable sequence is issued, surviving power transitions.

What is the purpose of the extra 64 bytes of EEPROM?

These additional bytes are reserved for device identification or tracking. They are accessed by raising A9 to 12V and using address locations 7FC0H to 7FFFH.