AT29C256-12PI

Memory IC Overview

The AT29C256-12PI is a 256K (32K x 8) 5-volt-only Flash memory component manufactured by Microchip Technology. It features a 120 ns access time and operates within a commercial temperature range of 0°C to +70°C. The device utilizes a 28-pin Plastic Dual Inline Package (PDIP). Electrical specifications include a maximum active current of 50 mA and a standby current of 300 µA, powered by a single 5V ± 10% supply.

Memory IC Feature Summary

• Supports in-system reprogrammability using only 5-volt power without requiring high input voltages.
• Enables page-based programming with internal address and data latches for 64-byte operations.
• Provides hardware and software mechanisms to protect against inadvertent program cycles.
• Includes data polling and toggle bit capabilities to detect the completion of program or erase cycles.

Memory IC Applications

• In-system code storage for embedded microcontroller applications
• Data retention for industrial control systems
• Firmware storage for consumer electronics

Memory IC Procurement Notes

Verify the package type matches the required 28-pin PDIP configuration. Confirm the suffix indicates the 120 ns speed grade and commercial temperature rating. Check for end-of-life status as this series may be discontinued. Ensure compatibility with existing 5V logic levels and interface requirements before procurement.

Memory IC Selection Notes

Select this component when a 256K capacity with parallel interface is required. The 120 ns speed suits moderate performance needs. Verify that the 5V-only operation aligns with the system power architecture. Consider the PDIP package constraints for board layout and thermal management in the final design.

Memory IC Part Context

This part belongs to the AT29C256 family of 5-volt-only Flash memories. It shares architectural similarities with other variants differing primarily in access speed and operating temperature ranges. The manufacturer transitioned from Atmel to Microchip Technology, maintaining the core functionality while updating product documentation and support structures.

Memory IC Replacement Considerations

AT29C256-12PC

Memory IC FAQ

How does the AT29C256-12PI indicate the end of a programming cycle?

The device uses Data Polling on I/O7, which outputs the complement of the loaded data during the cycle, and the Toggle Bit on I/O6, which toggles between states until the operation completes.

What are the specific hardware protections against accidental programming?

Hardware protection includes VCC sense inhibition below 3.8V, a 5 ms power-on delay, program inhibit via OE/CE/WE states, and noise filtering for pulses shorter than 15 ns on control inputs.