25AA640AT-E/SN

Memory IC Overview

The Microchip Technology 25AA640AT-E/SN is a 64-Kbit serial Electrically Erasable PROM featuring an SPI-compatible interface. It operates within a voltage range of 1.8V to 5.5V and supports clock frequencies up to 10 MHz at higher voltages. The device utilizes an 8192 x 8-bit organization with a 32-byte page size. It is housed in an 8-lead SOIC package and qualified for automotive applications under AEC-Q100 standards, supporting an extended temperature range from -40°C to +125°C.

Memory IC Feature Summary

• Supports Serial Peripheral Interface (SPI) communication with separate data input and output lines controlled by chip select and serial clock signals.
• Includes hardware write protection mechanisms such as block write protection, power-on/off data protection circuitry, and a dedicated write-protect pin.
• Features a hold function that allows suspension of serial transmission without resetting the sequence, facilitating host interrupt servicing.

Memory IC Applications

• Automotive electronic systems requiring AEC-Q100 qualification
• Microcontroller-based data storage for configuration parameters
• Industrial control systems needing non-volatile memory retention

Memory IC Procurement Notes

Verify the specific suffix 'E' confirms the extended temperature rating (-40°C to +125°C) and 'SN' denotes the SOIC package. Confirm the 'T' indicates tape and reel packaging if required for automated assembly. Ensure compatibility with the 1.8V minimum supply voltage requirement for the AA series variant.

Memory IC Selection Notes

Select this component when an SPI EEPROM with automotive qualification is necessary. The 25AA640A variant supports lower voltage operation down to 1.8V compared to the 25LC640A which starts at 2.5V. Consider the 32-byte page write limit and the need for software management of page boundary crossings during implementation.

Memory IC Part Context

This part belongs to the 25XX640A family of 64-Kbit serial EEPROMs manufactured by Microchip Technology. The family includes variants like the 25LC640A, distinguished primarily by their operating voltage ranges and temperature specifications. These devices are designed for high-reliability applications requiring robust data retention and endurance characteristics.

Memory IC Replacement Considerations

The 25LC640AT-E/SN serves as a functional substitute within the same family, though it requires a minimum supply voltage of 2.5V rather than 1.8V. Other compatible packages include TSSOP or MSOP variants with equivalent electrical specifications.

Memory IC FAQ

How does the HOLD pin function during serial communication?

The HOLD pin suspends transmission mid-sequence without resetting the serial pointer. Inputs SI, SCK, and SO enter a high-impedance state while held low, allowing the host to service interrupts before resuming communication.

What is the maximum page write capability?

The device supports writing up to 32 bytes per page. If a write operation attempts to cross a physical page boundary, the data wraps around to the beginning of the current page instead of proceeding to the next.