25C040X/ST

Memory IC Overview

The Microchip Technology 25C040X/ST is a 4 Kbit (512 x 8) serial Electrically Erasable PROM housed in an 8-lead TSSOP package. It operates within a voltage range of 4.5 V to 5.5 V and supports a maximum clock frequency of 3 MHz via a SPI-compatible interface. The device features industrial temperature ratings from -40°C to +85°C, with data retention exceeding 200 years and endurance up to 1 million cycles.

Memory IC Feature Summary

• Supports sequential read operations with automatic address pointer incrementation across the memory array.
• Includes hardware write protection via the WP pin and software-controlled block protection for specific array segments.
• Features a HOLD input that suspends serial communication without resetting the internal sequence state.

Memory IC Applications

• Microcontroller system configuration storage
• Calibration data retention
• Parameter logging in industrial devices

Memory IC Procurement Notes

Verify the 'X' suffix indicates the alternate pinout configuration specific to the ST package. Confirm the 'I' designation matches the required -40°C to +85°C operating range. Ensure the 4.5V minimum supply voltage aligns with the target system power rails before procurement.

Memory IC Selection Notes

Select this component when a 5V logic interface is required with SPI compatibility. The 25C040X variant offers a distinct pin arrangement compared to standard packages. Consider the 16-byte page write limit and self-timed cycle duration for timing-sensitive application designs.

Memory IC Part Context

This part belongs to the 25XX040 family of 4 Kbit serial EEPROMs. It shares functional similarities with the 25AA040 and 25LC040 but is distinguished by its 4.5V to 5.5V operating voltage range and specific automotive-grade temperature availability.

Memory IC Replacement Considerations

Datasheet notes indicate this series is not recommended for new designs; the 25AA040A or 25LC040A are suggested alternatives. Verify pinout compatibility if substituting with non-X variants or other manufacturers' 25-series parts.

Memory IC FAQ

What is the function of the HOLD pin?

The HOLD pin pauses serial communication while maintaining the current sequence state. Transitions on SI, SCK, and SO are ignored during this period, allowing the host to service higher priority interrupts.

How does the WP pin affect write operations?

When the WP pin is low, all writes to the array and STATUS register are disabled. When high, normal write operations proceed according to the Write Enable Latch status.