25LC040A-E/P

Overview

The Microchip Technology 25LC040A-E/P is a 4 Kbit (512 x 8-bit) Serial Electrically Erasable Programmable Read-Only Memory (EEPROM). It utilizes a SPI-compatible serial bus for data access, supporting a maximum clock frequency of 10 MHz. The device operates within a supply voltage range of 2.5 V to 5.5 V and is rated for an industrial temperature range of -40°C to +85°C. It is housed in an 8-lead PDIP package.

Feature Summary

• Supports sequential read operations and page write mode with up to 16 bytes per page.
• Includes built-in write protection mechanisms such as power-on/off data protection circuitry and a dedicated write-protect pin.
• Features a hold input that allows communication suspension without resetting the serial sequence.

Applications

• Microcontroller systems requiring non-volatile storage for configuration parameters.
• Embedded devices needing persistent storage for calibration data or device identifiers.
• Industrial control applications utilizing standard SPI interfaces for memory expansion.

Procurement Notes

Verify the specific suffix 'E' corresponds to the automotive temperature grade (-40°C to +125°C) if required, as datasheets may list Industrial ('I') grades separately. Confirm the 'P' suffix indicates the PDIP package type. Ensure the source documentation explicitly supports the 2.5V minimum voltage operation for this specific variant before finalizing procurement specifications.

Selection Notes

Select this component when a 4 Kbit capacity is sufficient for application requirements. The 2.5V to 5.5V operating range makes it suitable for systems powered by 3.3V or 5V rails. Consider the 10 MHz clock speed for high-throughput SPI applications. Verify that the 8-pin PDIP footprint aligns with the target PCB design constraints.

Part Context

This part belongs to the 25XX040A family of serial EEPROMs from Microchip Technology. The series includes variants like the 25AA040A and 25C040, which differ primarily in voltage ranges and temperature ratings. The 25LC040A specifically targets low-voltage applications while maintaining compatibility with standard SPI protocols used across various microcontroller architectures.

Replacement Considerations

The 25LC040A-I/P serves as a direct functional substitute with identical electrical characteristics but a lower industrial temperature rating (-40°C to +85°C). Other compatible parts include the 25AA040A, though it supports a wider voltage range down to 1.8V. Verify package and temperature specifications when substituting.

FAQ

How does the HOLD pin function during serial communication?

The HOLD pin suspends transmission to the device without resetting the serial sequence. When pulled low while SCK is low, inputs are ignored and SO goes high-impedance. Communication resumes when HOLD is brought high while SCK is low.

What is the maximum page size for write operations?

The device supports a page write mode of up to 16 bytes. All bytes in a single write operation must reside within the same physical page boundary.