25CS640-H/SN

Overview

The Microchip Technology 25CS640-H/SN is a 64-Kbit (8,192 x 8 bit) Serial EEPROM utilizing SPI-compatible bus communication. It features a 32-byte page size and supports byte or sequential reads and writes. The device includes a Security Register with a preprogrammed 128-bit serial number and a 32-byte user-programmable ID page. Built-in ECC logic corrects single-bit errors within four-byte readouts. Operating voltage ranges from 1.7V to 5.5V, with clock frequencies up to 20 MHz at VCC ≥ 4.5V. The -H suffix denotes an Extended temperature range of -40°C to +150°C.

Feature Summary

• Integrated Security Register containing a factory-programmed 128-bit unique serial number and a lockable 32-byte user ID page.
• Built-in Error Correction Code (ECC) logic capable of correcting one incorrectly read bit per four-byte readout sequence.
• Configurable Enhanced Write Protection Mode allowing independent partitioning of memory with unique protection behaviors.
• Programmable Undervoltage Lockout Detection circuit to inhibit write sequences during brown-out events.

Applications

• Automotive applications requiring AEC-Q100 qualification and high-temperature operation up to 150°C.
• Industrial systems needing reliable nonvolatile memory storage with enhanced data integrity via ECC.
• Consumer electronics requiring component serialization and secure identification through the unique serial number.

Procurement Notes

Verify that the 'H' suffix corresponds to the Extended temperature range (-40°C to +150°C) and the 'SN' package designation matches the required 8-Lead SOIC form factor. Confirm the specific revision level against the latest datasheet DS20005943D to ensure compatibility with legacy parts like the 25AA640A/25LC640A if pin-for-pin replacement is intended.

Selection Notes

Select this component when high-temperature reliability is critical, as indicated by the -H rating. The inclusion of ECC makes it suitable for environments where data corruption risks are higher. Ensure the host controller supports SPI Modes 0 or 3 and can handle the maximum clock frequency requirements based on the available supply voltage.

Part Context

This part belongs to the 25CS series of Serial EEPROMs, which are designed for backward compatibility with older generations like the 25AA640A and AT25C640B. The series emphasizes security and reliability through features like unique serial numbers and error correction, targeting automotive and industrial markets where standard consumer-grade components may not suffice.

Replacement Considerations

The datasheet confirms backward compatibility with the 25AA640A, 25LC640A, and AT25C640B. Verify that the original part's temperature rating meets the application requirements, as the 25CS640-H offers extended range capabilities compared to standard industrial variants.