25LC640A-I/ST

Overview

The Microchip Technology 25LC640A-I/ST is a 64-Kbit (8192 x 8-bit) Serial Electrically Erasable PROM accessed via an SPI-compatible bus. It operates within a voltage range of 2.5V to 5.5V and supports clock frequencies up to 10 MHz at 5.5V. The device features a 32-byte page size, self-timed erase/write cycles with a maximum duration of 5 ms, and industrial temperature support from -40°C to +85°C.

Feature Summary

• Supports serial communication through standard SPI signals including SCK, SI, SO, and CS.
• Includes hardware write protection controlled by the WP pin and STATUS register bits.
• Features a HOLD input to pause serial transmission without resetting the sequence.

Applications

• Data storage in microcontroller systems requiring non-volatile memory
• Configuration parameter retention in embedded devices
• Calibration data logging for industrial sensors

Procurement Notes

Verify that the ordering suffix 'I' corresponds to the Industrial temperature range (-40°C to +85°C). Confirm the 'ST' suffix indicates the 8-Lead TSSOP package type. Ensure the specific variant matches the required voltage specifications, as the 25LC640A series requires a minimum supply voltage of 2.5V.

Selection Notes

Select this component when an SPI interface is preferred over parallel architectures. The 25LC640A is suitable for applications needing moderate density with low standby current. Verify that the system voltage remains above 2.5V to ensure proper operation. Consider the 32-byte page write limit when designing firmware to optimize write performance.

Part Context

This part belongs to the 25XX640A family of 64-Kbit Serial EEPROMs. It shares functional compatibility with the 25AA640A, though the latter supports a lower minimum voltage of 1.8V. The 25LC640A is specifically designed for industrial environments where a 2.5V minimum supply is acceptable.

Replacement Considerations

The 25AA640A-I/ST is a direct functional substitute within the same package, offering broader voltage compatibility down to 1.8V. Other variants such as 25LC640A-I/SN or 25LC640A-I/P provide identical electrical characteristics but utilize different physical packages.