25LC640AT-H/SN

Overview

The Microchip Technology 25LC640AT-H/SN is a mid-density serial EEPROM with a 64 Kbit (8K x 8) organization. It operates on a 2.5V to 5.5V supply and supports SPI communication at up to 5 MHz for VCC ≥ 4.5V, or 3 MHz for lower voltages. The device features a page size of 32 bytes and utilizes an 8-lead SOIC package. It is rated for extended industrial temperatures ranging from -40°C to +150°C.

Feature Summary

• Supports block-level write protection allowing configuration to protect none, one-quarter, one-half, or the entire memory array.
• Includes hardware write protection via the WP pin combined with the WPEN status register bit.
• Features a HOLD input that suspends serial communication without resetting the internal address pointer.

Applications

• Industrial control systems requiring high-temperature reliability
• Automotive electronics operating under extended thermal conditions
• Data logging applications needing non-volatile storage

Procurement Notes

Verify the specific suffix 'H' confirms the extended temperature range (-40°C to +150°C). Confirm the 'SN' designation matches the required 8-lead narrow SOIC package dimensions. Ensure the 'T' indicates tape-and-reel packaging if automated assembly is planned. Cross-reference the datasheet revision to confirm current electrical characteristics.

Selection Notes

Select this component when designs require operation above standard industrial limits up to 150°C. The 64 Kbit capacity suits moderate data storage needs. Verify system voltage compatibility within the 2.5V to 5.5V range. Consider the 32-byte page size for write efficiency requirements compared to byte-only operations.

Part Context

This part belongs to the 25LCXXX family of mid-density serial EEPROMs. It shares architectural similarities with other densities in the series but offers specific 64 Kbit capacity. The device interfaces directly with SPI ports found in various microcontroller families.

FAQ

How does the HOLD pin function during communication?

The HOLD pin pauses serial communication when pulled low while SCK is low. It maintains the current state without resetting the address pointer, resuming upon release.

What determines the maximum clock frequency?

The maximum clock frequency depends on the supply voltage. It is 5 MHz when VCC is between 4.5V and 5.5V, and reduces to 3 MHz when VCC is between 2.5V and 4.5V.