25LC040A-I/ST

Overview

The Microchip Technology 25LC040A-I/ST is a 4 Kbit (512 x 8-bit) Serial Electrically Erasable Programmable Read-Only Memory (EEPROM). It operates within a supply voltage range of 2.5V to 5.5V and supports a maximum clock frequency of 10 MHz. The device utilizes an SPI-compatible serial bus with SCK, SI, SO, CS, WP, and HOLD pins. It features industrial temperature operation from -40°C to +85°C in an 8-lead TSSOP package.

Feature Summary

• Supports sequential read operations and page write mode for up to 16 bytes per cycle.
• Includes built-in hardware write protection via the WP pin and software block protection for none, 1/4, 1/2, or all of the array.
• Features power-on/off data protection circuitry and a write enable latch to prevent inadvertent writes.

Applications

• Microcontroller system data storage
• Configuration parameter retention
• Calibration value storage

Procurement Notes

Verify that the ordering suffix 'I' corresponds to the Industrial temperature grade (-40°C to +85°C) and 'ST' indicates the 8-lead TSSOP package. Confirm the specific voltage range requirements align with the 2.5V to 5.5V specification for the 25LC040A series before procurement.

Selection Notes

Select this component when a 4 Kbit EEPROM is required with a 2.5V minimum operating voltage. The 25LC040A differs from the 25AA040A by its higher minimum voltage threshold. Ensure the application environment remains within the specified industrial temperature range and utilizes standard SPI signaling.

Part Context

This part belongs to the 25XX040A family of 4 Kbit SPI Serial EEPROMs. It shares architectural similarities with the 25AA040A but is distinguished by its 2.5V to 5.5V operating voltage range, whereas the AA variant supports 1.8V. Both share identical memory organization and interface protocols.

Replacement Considerations

The 25LC040A-I/SN serves as a direct package alternative using the 8-lead SOIC format. Other variants within the 25LC040A family may be considered if different package types are required, provided the electrical specifications remain compatible.

FAQ

How does the HOLD pin function during communication?

The HOLD pin allows the user to pause serial communication without resetting the sequence. Transitions on SI, SCK, and SO are ignored while HOLD is low, and communication resumes when HOLD is brought high while SCK is low.

What happens if a page write crosses a physical page boundary?

If a page write attempts to cross a boundary, the data wraps around to the beginning of the current page, overwriting existing data instead of proceeding to the next page.