25AA640AXT-I/ST

Memory IC Overview

The Microchip Technology 25AA640AXT-I/ST is a 64-Kbit (8192 x 8-bit) Serial Electrically Erasable PROM featuring an SPI-compatible interface. It operates within a supply voltage range of 1.8V to 5.5V and supports clock frequencies up to 10 MHz at higher voltages. The device utilizes an 8-lead TSSOP package with rotated pinout configuration, suitable for surface-mount applications. It functions within the industrial temperature range of -40°C to +85°C.

Memory IC Feature Summary

• Supports high-speed serial communication via SPI bus with hold functionality for interrupt servicing
• Includes hardware write protection mechanisms and block-level array protection
• Features low-power CMOS technology with standby current consumption
• Provides high reliability with significant endurance cycles and long data retention

Memory IC Applications

• Microcontroller system data storage
• Configuration parameter storage
• Calibration data retention
• Automotive electronics requiring AEC-Q100 qualification

Memory IC Procurement Notes

Verify the specific suffix 'XT' indicates the rotated pinout variant compatible with the standard TSSOP footprint but with swapped VCC and HOLD pins relative to standard orientation. Confirm the 'I' designation matches the required industrial temperature range for the target application environment. Ensure the source documentation explicitly supports the 1.8V minimum operating voltage for this specific part number variant.

Memory IC Selection Notes

Select this component when a 64-Kbit non-volatile memory solution is required with SPI connectivity and low power consumption. The 1.8V minimum voltage capability makes it suitable for systems operating below the 2.5V threshold typical of other EEPROM variants. The rotated pinout option provides layout flexibility for dense PCB designs while maintaining compatibility with standard 8-lead packages.

Memory IC Part Context

This part belongs to the 25AA640A/25LC640A family of 64-Kbit SPI Serial EEPROMs manufactured by Microchip Technology. The 'AA' prefix denotes the 1.8V to 5.5V voltage range, distinguishing it from the 'LC' series which typically starts at 2.5V. The 'XT' suffix specifically identifies the TSSOP package with rotated pinout configuration.

Memory IC Replacement Considerations

Direct substitutes include the 25AA640A-I/ST (standard pinout) or 25LC640A series parts if voltage requirements align. Verify pinout compatibility before swapping rotated versus standard TSSOP packages.

Memory IC FAQ

What is the function of the HOLD pin?

The HOLD pin suspends serial communication without resetting the sequence, allowing the host to service higher priority interrupts.

How is write protection configured?

Write protection is managed via the STATUS register using Block Protection (BP) bits for array segments and the WP pin combined with the WPEN bit for hardware protection.