25LC040T-I/SN

Overview

The Microchip Technology 25LC040T-I/SN is a 4 Kbit (512 x 8-bit) serial Electrically Erasable PROM. It utilizes a Serial Peripheral Interface (SPI) compatible bus for communication, requiring SCK, SI, SO, and CS signals. The device operates within a voltage range of 2.5V to 5.5V with a maximum clock frequency of 2 MHz. It supports self-timed erase and write cycles with a maximum duration of 5 ms. The component is housed in an 8-lead Plastic Small Outline package (SOIC) and is rated for industrial operating temperatures from -40°C to +85°C.

Feature Summary

• Supports hardware write protection via the WP pin and software block protection through the STATUS register.
• Includes built-in power-on data protection circuitry and a write enable latch to prevent inadvertent writes.
• Features a HOLD input that allows suspension of serial communication without resetting the sequence.

Applications

• Data storage in microcontroller systems using SPI ports
• Configuration parameter retention in embedded devices
• Calibration value storage in industrial instrumentation

Procurement Notes

Verify the specific suffix 'I' corresponds to the Industrial temperature range (-40°C to +85°C) and 'SN' indicates the 8-lead SOIC package. Confirm the 'T' suffix aligns with tape and reel packaging requirements. Ensure the design accommodates the 2.5V to 5.5V supply voltage constraints and 2 MHz maximum clock speed specified for this variant.

Selection Notes

Select this component when a low-power, non-volatile memory solution with SPI interface is required for industrial environments. It is suitable for applications needing moderate endurance and long data retention. Note that the datasheet indicates this series is not recommended for new designs; consider newer alternatives like the 25LC040A if available.

Part Context

This part belongs to the 25XX040 family of 4 Kbit serial EEPROMs manufactured by Microchip Technology. The family includes variants such as the 25AA040 and 25C040, which differ primarily in supply voltage ranges and maximum clock frequencies. The 25LC040 specifically targets applications requiring operation down to 2.5V.

Replacement Considerations

Public confirmed substitute part numbers: None identified in source material.

FAQ

How does the HOLD pin function during serial communication?

The HOLD pin suspends transmission to the device while in the middle of a serial sequence without resetting the sequence. Transitions on SI, SCK, and SO are ignored while held low, allowing the host to service higher priority interrupts.

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

Upon power-up, the device enters low-power Standby mode, the write enable latch is reset, and the SO pin is in a high-impedance state. A low level on CS is required to enter the active state.