25LC040A-I/SN

Overview

The Microchip Technology 25LC040A-I/SN is a 4 Kbit Serial Electrically Erasable Programmable Read-Only Memory (EEPROM) utilizing an SPI-compatible serial bus. It features a 512 x 8-bit organization with a 16-byte page write capability. The device operates within a voltage range of 2.5V to 5.5V and supports a maximum clock frequency of 10 MHz at 5.5V. It includes block write protection, self-timed erase/write cycles up to 5 ms, and high reliability with 1,000,000 endurance cycles and over 200 years data retention.

Feature Summary

• Supports Serial Peripheral Interface (SPI) compatible communication with separate data in and out lines.
• Includes hardware write-protect pin and software-based block protection for none, 1/4, 1/2, or all array segments.
• Features built-in power-on/off data protection circuitry and a write enable latch mechanism.
• Provides hold functionality to pause serial transmission without resetting the sequence.

Applications

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

Procurement Notes

Verify the specific suffix 'I' confirms Industrial temperature range (-40°C to +85°C) and 'SN' denotes the 8-lead SOIC package. Confirm the 'LC' prefix indicates the 2.5V to 5.5V operating voltage range, distinct from the AA variant. Ensure compliance requirements match the Pb-Free and RoHS status documented in the datasheet.

Selection Notes

Select this component when an SPI interface is required for non-volatile storage in industrial environments. The 2.5V minimum supply voltage distinguishes it from lower-voltage variants. Consider the 16-byte page size limitation for write operations and the availability of hardware write protection via the WP pin for critical data integrity applications.

Part Context

This part belongs to the 25XX040A family of 4 Kbit EEPROMs. The 25LC040A specifically targets applications requiring a 2.5V to 5.5V supply range, whereas the 25AA040A supports 1.8V operation. Both share identical pinouts and instruction sets but differ in electrical characteristics and temperature grades.

Replacement Considerations

The 25AA040A is a functional substitute if the application supports 1.8V operation. Other 4 Kbit SPI EEPROMs from different manufacturers may require firmware adjustments due to differing instruction sets or timing parameters.

FAQ

How does the HOLD pin function during serial communication?

The HOLD pin suspends transmission when pulled low while SCK is low. Transitions on SI, SCK, and SO are ignored during this state, allowing the host to service interrupts. 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 writing to the next page. Software must prevent such operations.