25AA040X/ST

Memory IC Overview

The Microchip Technology 25AA040X/ST is a 4 Kbit (512 x 8) serial Electrically Erasable PROM utilizing an SPI-compatible interface. It operates within a voltage range of 1.8V to 5.5V and supports a maximum clock frequency of 1 MHz. The device features a TSSOP-8 package with industrial temperature ratings from -40°C to +85°C. Key electrical characteristics include a typical read current of 500 μA, write current of 3 mA, and standby current of 500 nA. It offers 1 million cycle endurance, over 200 years data retention, and ESD protection exceeding 4000V.

Memory IC Feature Summary

• Low-power CMOS technology with minimal active and standby currents
• Hardware write protection via dedicated pin and software-controlled block protection
• Self-timed erase and write cycles with automatic address pointer incrementation
• Communication pause capability through the HOLD input for bus arbitration

Memory IC Applications

• Microcontroller system data storage
• Configuration parameter retention
• Calibration value memory
• Device identification storage

Memory IC Procurement Notes

Verify that the specific ordering suffix matches the required package type and temperature grade. Confirm the presence of the 'X' designation indicates the alternate pinout configuration available exclusively in the ST package. Ensure compatibility with the host controller's SPI mode settings before procurement.

Memory IC Selection Notes

Select this component when low-voltage operation down to 1.8V is required alongside standard SPI connectivity. The X variant provides an alternative pin arrangement compared to standard ST packages, necessitating careful PCB layout review. Consider the 16-byte page write limitation and internal write cycle duration during high-frequency data logging applications.

Memory IC Part Context

This part belongs to the 25XX040 family of 4 Kbit serial EEPROMs. It shares architectural similarities with the 25LC040 and 25C040 but differs in minimum operating voltage and maximum clock speed specifications. The datasheet notes it is not recommended for new designs, suggesting the use of updated A-series variants instead.

Memory IC Replacement Considerations

Public confirmed substitute part numbers: 25AA040AT-I/SN, 25AA040A-I/MS, 25LC040XT/ST, 25C040XT-I/ST, 25LC040AT-I/OT, 25LC040AT-E/SN, 25AA040-I/P.