25LC040/SN

Overview

The Microchip Technology 25LC040/SN is a 4 Kbit (512 x 8) serial Electrically Erasable PROM. It operates within a voltage range of 2.5V to 5.5V and supports a maximum clock frequency of 2 MHz. The device utilizes an SPI-compatible interface with SCK, SI, SO, CS, HOLD, and WP pins. It features self-timed write cycles of up to 5 ms, 1 million cycle endurance, and data retention exceeding 200 years. The component is housed in an 8-lead Plastic Small Outline (SOIC) package.

Feature Summary

• Supports hardware write protection via the dedicated WP pin and software-controlled block protection for specific array segments.
• Includes built-in power-on/off data protection circuitry and a write enable latch to prevent inadvertent writes.
• Allows communication pausing through the HOLD pin without resetting the active serial sequence.

Applications

• Microcontroller system data storage
• Configuration parameter storage
• Calibration value retention

Procurement Notes

Verify that the ordering suffix matches the required specifications. Confirm the package type corresponds to the SN designation for the 8-lead SOIC format. Ensure the temperature grade aligns with the intended operational environment. Check for any specific environmental compliance requirements relevant to the deployment region.

Selection Notes

Select this component when a low-pin-count nonvolatile memory solution is required for small data sets. The 2.5V minimum supply voltage makes it suitable for systems operating at standard logic levels. Consider the 16-byte page size limitation for write operations during system architecture design.

Part Context

This part belongs to the 25XX040 family, which includes variants like the 25AA040 and 25C040. These devices share identical functional architectures but differ in supply voltage ranges and temperature ratings. The 25LC040 specifically targets industrial applications requiring a 2.5V to 5.5V operating window.

Replacement Considerations

Datasheets indicate the 25LC040A as a recommended alternative for new designs. Verify compatibility regarding package dimensions and electrical characteristics before substitution.

FAQ

How does the HOLD pin function during serial communication?

The HOLD pin suspends transmission mid-sequence without resetting the serial pointer. Inputs are ignored while held low, allowing the host to service higher priority interrupts.

What happens to the write enable latch upon power-up?

The device powers on in standby mode with the write enable latch reset, ensuring that no write operations can occur until explicitly enabled by the WREN instruction.