AT28HC256-12JU-070

Memory IC Overview

The AT28HC256-12JU-070 is a 256-Kbit (32,768 x 8) high-speed parallel EEPROM manufactured by Microchip Technology. It features a 120 ns access time and operates on a single 5V ± 10% supply within the industrial temperature range of -40°C to +85°C. The device supports page write operations for up to 64 bytes with an internal control timer. It includes hardware and software data protection mechanisms, such as VCC sense and software data protection algorithms. Endurance options include standard or extended cycles, with data retention specified at 10 years.

Memory IC Feature Summary

• Supports automatic page write operations with internal address and data latches for up to 64 bytes.
• Includes hardware and software data protection to prevent inadvertent writes during power transitions.
• Features DATA Polling and Toggle Bit capabilities for efficient end-of-write cycle detection.
• Provides an extra 64 bytes of EEPROM memory dedicated to device identification or tracking.

Memory IC Applications

• Industrial systems requiring nonvolatile storage with robust data protection.
• Embedded applications needing fast read access times and low standby current.
• Systems utilizing software-controlled data protection mechanisms for security.
• Devices requiring specific memory locations for unique identification or tracking.

Memory IC Procurement Notes

Verify the specific endurance rating (standard vs. extended) and write cycle time (standard vs. fast) associated with the suffix codes in the part number. Confirm the package type matches the required PCB layout, as the series offers both PLCC and SOIC options. Ensure the design accounts for the 5V supply requirement and industrial temperature range specifications.

Memory IC Selection Notes

Select this component when a high-speed parallel interface is required for 256-Kbit nonvolatile storage. Consider the AT28HC256-12JU-070 for applications needing 120 ns access times and industrial temperature operation. Evaluate the need for extended endurance or fast write cycles based on system write frequency requirements. Ensure compatibility with CMOS and TTL logic levels for seamless integration.

Memory IC Part Context

The AT28HC256 belongs to Microchip's high-performance Electrically Erasable and Programmable Read-Only Memory family. It is designed to be accessed like Static RAM, simplifying system design by eliminating the need for external components during read or write cycles. The device utilizes advanced nonvolatile CMOS technology to achieve low power dissipation while maintaining high reliability and manufacturability standards.

Memory IC Replacement Considerations

Check datasheet pinouts and electrical characteristics for cross-referencing. Verify if alternative parts support the same page write functionality and data protection features. Ensure voltage and temperature ranges match application requirements before substitution.

Memory IC FAQ

How can the end of a write cycle be detected?

The end of a write cycle can be detected using DATA Polling on I/O7 or by monitoring the Toggle Bit on I/O6.

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

The additional 64 bytes are available for device identification or tracking purposes and can be accessed by raising A9 to 12V.

Does Software Data Protection persist through power cycles?

Yes, once enabled, Software Data Protection remains active during power-up and power-down conditions until disabled by the specific command sequence.