25LC040XT/ST

Overview

The Microchip Technology 25LC040XT/ST is a 4 Kbit (512 x 8-bit) serial Electrically Erasable PROM housed in an 8-lead TSSOP package. It operates on a supply voltage range of 2.5V to 5.5V with a maximum clock frequency of 2 MHz. The device utilizes a standard SPI-compatible interface requiring SCK, SI, SO, and CS signals. Key electrical parameters include a typical read current of 500 μA, write current of 3 mA, and standby current of 500 nA. It supports industrial temperature ranges from -40°C to +85°C.

Feature Summary

• Supports sequential reading across the memory array with automatic address pointer incrementation.
• Features hardware write protection via the WP pin to disable all array writes when asserted low.
• Includes self-timed erase and write cycles that operate independently after initiation.
• Provides block write protection capabilities allowing selective protection of none, one-quarter, one-half, or the entire memory array.

Applications

• Microcontroller systems requiring non-volatile data storage for configuration settings
• Industrial control applications needing reliable parameter retention
• Embedded devices utilizing SPI interfaces for low-pin-count memory expansion

Procurement Notes

Verify the specific suffix 'XT' indicates tape and reel packaging and potential alternate pinout configurations if applicable to the ST package variant. Confirm the 'I' temperature grade corresponds to the required industrial operating range. Ensure compatibility with the host system's SPI voltage levels and timing constraints before finalizing procurement specifications.

Selection Notes

Select this component for designs requiring low-power consumption and robust data retention exceeding 200 years. Consider the 2 MHz clock speed sufficient for moderate throughput requirements. Evaluate the 16-byte page write capability against application update frequencies. Ensure the TSSOP package fits the available PCB real estate and thermal management strategy.

Part Context

This part belongs to the 25XX040 family of 4 Kbit serial EEPROMs manufactured by Microchip Technology. It shares architectural similarities with the 25AA040 and 25C040 variants, differing primarily in supply voltage ranges and maximum clock frequencies. The datasheet notes that this specific generation is not recommended for new designs, suggesting consideration of newer alternatives like the 25LC040A series.

Replacement Considerations

Public confirmed substitute part numbers: 25LC040AT-I/ST, 25LC040T-I/SN.