25CS320-E/ST

Overview

The Microchip Technology 25CS320-E/ST is a 32-Kbit SPI Serial EEPROM organized as 4,096 x 8 bits. It operates within a voltage range of 1.7V to 5.5V and supports clock frequencies up to 20 MHz at VCC ≥ 4.5V. The device features an 8-lead TSSOP package and functions across an extended temperature range of -40°C to +125°C. Key specifications include a maximum write current of 5.0 mA, standby current of 1.0 µA, and data retention exceeding 200 years.

Feature Summary

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

Applications

• Automotive applications requiring AEC-Q100 qualified nonvolatile memory storage.
• Industrial systems needing reliable data logging with enhanced write protection.
• Consumer electronics utilizing the globally unique serial number for product serialization.

Procurement Notes

Verify that the ordering suffix 'E' corresponds to the Extended temperature range (-40°C to +125°C) and 'ST' indicates the 8-lead TSSOP package. Confirm the specific datasheet revision matches the required electrical characteristics. Ensure compatibility with the host controller's SPI mode and voltage levels before finalizing procurement.

Selection Notes

Select this component when high reliability and data integrity are critical due to the built-in ECC logic. The Extended temperature rating makes it suitable for harsh environments where standard industrial parts may fail. The configurable write protection modes offer flexibility for securing sensitive application data against unauthorized modification.

Part Context

The 25CS320 belongs to Microchip's CS series of Serial EEPROMs, designed for backward compatibility with legacy devices like the 25AA320A and AT25320B. This series emphasizes security through unique identification and robust protection mechanisms, positioning it as a secure storage solution for modern embedded systems requiring traceability.

Replacement Considerations

The 25CS320 is backward compatible with the 25AA320A, 25LC320A, and AT25320B. When replacing these older components, verify that the system can support the Enhanced Write Protection features and that the pinout remains identical to ensure a drop-in replacement without hardware modifications.

FAQ

How does the ECC logic function?

The built-in ECC scheme corrects up to one incorrectly read bit within a four-byte readout sequence and sets a status flag in the STATUS register if an error was detected and corrected.

What is the purpose of the HOLD pin?

The HOLD pin allows the host to pause serial communication without resetting the sequence, enabling the processor to service higher priority interrupts while maintaining the current state.