25CSM04-I/SN

Overview

The Microchip Technology 25CSM04-I/SN is a 4-Mbit SPI Serial EEPROM organized as 524,288 x 8 bytes. It operates within a voltage range of 2.5V to 5.5V and supports clock frequencies up to 8 MHz at VCC ≥ 3.0V or 5 MHz at VCC ≥ 2.5V. The device features a Security Register with a preprogrammed 128-bit serial number and a 256-byte user-programmable lockable ID page. Built-in ECC logic corrects single-bit errors per four-byte read. It offers configurable write protection via Legacy Block Protection or Enhanced Memory Partitioning modes. The component provides over one million erase/write cycles and data retention exceeding 100 years.

Feature Summary

• Integrated Security Register containing a factory-programmed 128-bit unique serial number and a 256-byte user-programmable lockable ID page for secure identification.
• Built-in Error Correction Code (ECC) logic capable of correcting up to one incorrectly read bit within every four bytes retrieved from the memory array.
• Configurable write protection architecture supporting both Legacy Block Protection modes and Enhanced Write Protection modes with independent user-definable memory partitions.
• JEDEC-compliant Identification Register providing electronic querying capabilities for Manufacturer ID, Device ID, and Extended Device Information.

Applications

• Consumer electronics requiring reliable nonvolatile storage
• Industrial applications demanding dependable memory performance
• Medical equipment needing secure data retention

Procurement Notes

Verify that the ordering suffix 'I' corresponds to the Industrial temperature range (-40°C to +85°C). Confirm the package type matches the SOIC-8 specification. Ensure the specific revision level aligns with your design requirements. Cross-reference the JEDEC standard compliance for identification registers if system integration depends on it. Validate voltage specifications against your power supply rails.

Selection Notes

Select this component when high reliability and security are required alongside standard EEPROM functionality. The built-in ECC ensures data integrity during reads, while the flexible write protection schemes allow for robust configuration management. The inclusion of a unique serial number simplifies manufacturing serialization processes. Consider the enhanced partitioning features if distinct memory zones require different protection levels.

Part Context

The 25CSM04 belongs to Microchip's CS series of SPI Serial EEPROMs, which are optimized for applications requiring secure and dependable nonvolatile storage. This series integrates advanced security features like unique serial numbers and lockable ID pages directly into the memory structure. The devices support broad voltage ranges and offer various package options to suit different form factors.

Replacement Considerations

Check datasheets for other 25CSMxx models in the CS series for capacity variations. Verify compatibility with existing SPI interface protocols and voltage levels. Ensure replacement parts maintain similar ECC and write protection feature sets if these are critical to the application design.

FAQ

How does the ECC logic function within the 25CSM04?

The built-in ECC logic can correct up to one incorrectly read bit within every four bytes read out from the memory array. It also includes a flag in the STATUS register to report detected and corrected errors.

What is the difference between Legacy and Enhanced Write Protection modes?

Legacy mode uses Block Protection bits in the STATUS register to protect quarter, half, or entire arrays. Enhanced mode segments memory into independent partitions defined by Memory Partition Registers, allowing unique protection behavior for each zone.

Can the Security Register be permanently locked?

Yes, the user-programmable portion of the Security Register can be permanently write-protected via a software sequence, preventing any further alterations to the data.