25LC640AT-E/ST

Overview

The Microchip Technology 25LC640AT-E/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 higher voltages. The device features a 32-byte page size, self-timed write cycles with a maximum duration of 5 ms, and high endurance rated for 1,000,000 erase/write cycles. It includes block write protection and data retention exceeding 200 years. The component is housed in an 8-lead TSSOP package and is qualified for extended industrial temperature ranges from -40°C to +125°C.

Feature Summary

• Supports serial communication via a standard four-wire SPI interface including Chip Select, Serial Clock, Serial Input, and Serial Output lines.
• Incorporates hardware and software write protection mechanisms, including a dedicated Write-Protect pin and programmable block protection bits within the Status Register.
• Features a Hold input that allows suspension of serial transmission without resetting the sequence, facilitating host interrupt handling.

Applications

• Data storage for system configuration parameters and calibration constants
• Logging operational history or event logs in embedded controllers
• Storing unique identifiers or security keys in non-volatile memory

Procurement Notes

Verify the specific ordering suffix 'E' confirms the extended temperature rating (-40°C to +125°C) and 'T' indicates tape-and-reel packaging. Confirm the 'ST' suffix corresponds to the 8-lead TSSOP package type. Ensure the voltage range requirement aligns with the 2.5V minimum specification for the LC variant. Cross-reference the datasheet revision to ensure compatibility with current manufacturing processes.

Selection Notes

Select this part when an SPI interface is required for non-volatile storage in high-temperature environments. The 25LC640A series is suitable for applications needing robust data retention and high endurance. Consider the 25AA640A if lower voltage operation down to 1.8V is necessary, as it shares the same functional architecture but differs in supply voltage specifications.

Part Context

This component belongs to the 25XX640A family of 64-Kbit Serial EEPROMs manufactured by Microchip Technology. The family includes variants like the 25AA640A, which supports a wider voltage range starting at 1.8V. The 25LC640A specifically targets applications requiring a 2.5V minimum supply voltage while maintaining compatibility with standard SPI protocols and offering high-speed read capabilities.

Replacement Considerations

The 25AA640A is a functional substitute within the same family, differing primarily in its support for lower supply voltages down to 1.8V. Other compatible parts include variants with different package options such as MSOP or SOIC, provided the temperature grade and pinout remain consistent with the design requirements.