25LC640A-M/SN

Overview

The Microchip Technology 25LC640A-M/SN is a 64 kbit Serial Electrically Erasable PROM housed in an 8-lead SOIC package. It features an SPI-compatible interface with a maximum clock frequency of 10 MHz and operates within a supply voltage range of 2.5V to 5.5V. The device supports an extended industrial temperature range from -55°C to +125°C, ensuring reliable performance in demanding environments.

Feature Summary

• Supports serial communication via standard SPI bus signals including SCK, SI, SO, and CS.
• Includes a HOLD pin to pause transmission without resetting the sequence for interrupt handling.
• Provides hardware write protection through the WP pin combined with STATUS register configuration.
• Features self-timed erase and write cycles with automatic address pointer incrementation.

Applications

• Data logging in industrial control systems
• Configuration storage for microcontroller-based devices
• Parameter retention in automotive electronics

Procurement Notes

Verify the specific ordering suffix '-M/SN' confirms the extended temperature rating (-55°C to +125°C) and the 8-lead SOIC package type. Ensure compatibility with system voltage levels (2.5V to 5.5V) and confirm that the manufacturer datasheet DS22144A applies to this exact part number variant before finalizing procurement.

Selection Notes

Select this component when extended temperature operation up to 125°C is required alongside standard SPI EEPROM functionality. The 8K x 8 organization fits applications needing moderate non-volatile storage. Verify that the 32-byte page size aligns with the host controller's write buffer capabilities to prevent data loss during page boundary crossings.

Part Context

This device belongs to the 25LC640A family of 64-kbit serial EEPROMs manufactured by Microchip Technology. It shares architectural similarities with other members like the 25AA640A but differs in operating temperature specifications. The 'M' suffix specifically denotes the extended temperature grade compared to the standard industrial 'I' grade variants.

Replacement Considerations

Direct substitutes include other 25LC640A variants with matching package and temperature ratings, such as 25LC640A-I/SN for lower temperature requirements. Cross-manufacturer equivalents must be verified against pinout and electrical characteristics.

FAQ

How does the HOLD pin function during serial communication?

The HOLD pin allows the user to pause serial communication without resetting the sequence. When pulled low while SCK is low, inputs are ignored until the pin is released high.

What is the maximum internal write cycle time?

The internal write cycle time is a maximum of 5 ms, initiated on the rising edge of CS after a valid write sequence.