25AA256-E/ST

Memory IC Overview

The Microchip Technology 25AA256-E/ST is a 256 Kbit Serial Electrically Erasable PROM featuring a 32,768 x 8-bit organization. It utilizes an SPI-compatible serial bus with a maximum clock frequency of 10 MHz. The device operates within a supply voltage range of 1.8V to 5.5V and supports an extended industrial temperature range from -40°C to +125°C. It includes block write protection, power-on data protection, and a hold pin for pausing communication. The component is housed in an 8-lead TSSOP package.

Memory IC Feature Summary

• Supports high-speed SPI communication with up to 10 MHz clock frequency
• Includes hardware write protection via WP pin and software block protection
• Features built-in power-on/off data protection circuitry
• Allows serial communication pause via dedicated HOLD input

Memory IC Applications

• Microcontroller system data storage
• Configuration parameter retention
• Calibration data logging
• Device identification storage

Memory IC Procurement Notes

Verify the specific suffix 'E' indicates the extended temperature grade (-40°C to +125°C) and 'ST' denotes the 8-lead TSSOP package. Confirm RoHS compliance status as per current manufacturer documentation. Ensure the ordering part number matches the required voltage and interface specifications before procurement.

Memory IC Selection Notes

Select this component when an SPI interface is required for non-volatile memory applications. The 25AA256 variant specifically supports lower voltage operation starting at 1.8V compared to the 25LC256 series. Consider the extended temperature rating if the application environment exceeds standard industrial limits.

Memory IC Part Context

This EEPROM belongs to the 25XX256 family, which shares functional similarities with the 25LC256 and 25AA256 devices. The primary distinction lies in the operating voltage range and temperature ratings. The 25AA256 is designed for broader voltage compatibility including low-voltage systems.

Memory IC Replacement Considerations

25LC256-E/ST

Memory IC FAQ

How does the HOLD pin function during serial communication?

The HOLD pin allows the host to pause serial communication without resetting the sequence. When pulled low while SCK is low, the SO pin goes high-impedance and input transitions are ignored until HOLD is released.

What is the purpose of the Write Enable Latch (WEL)?

The WEL bit must be set via the WREN instruction before any write operation can occur. It is automatically reset after power-up, a successful write, or execution of the WRDI instruction to prevent inadvertent writes.