25AA040-I/P

Memory IC Overview

The Microchip Technology 25AA040-I/P is a 4 Kbit (512 x 8-bit) serial Electrically Erasable PROM. It operates within a supply voltage range of 1.8V to 5.5V and supports a maximum clock frequency of 1 MHz. The device utilizes an SPI-compatible interface with separate data in (SI) and data out (SO) lines, synchronized by a clock input (SCK). Access is controlled via a Chip Select (CS) input, and communication can be paused using the HOLD pin. The component features block write protection, self-timed erase/write cycles, and high reliability with over 1 million endurance cycles and greater than 200 years of data retention.

Memory IC Feature Summary

• Supports low-power CMOS technology with typical standby current of 500 nA
• Includes built-in hardware write protection via WP pin and software-based block protection
• Features power-on/off data protection circuitry and a write enable latch
• Provides sequential read capability with automatic address pointer increment

Memory IC Applications

• Microcontroller system data storage
• Configuration parameter storage
• Calibration data retention
• Device identification information storage

Memory IC Procurement Notes

Verify that the specific ordering suffix matches the required package type, as the 'P' designation indicates an 8-lead Plastic Dual In-line Package. Confirm the temperature grade corresponds to industrial specifications (-40°C to +85°C). Ensure the design accounts for the device being marked as not recommended for new designs, suggesting evaluation of newer alternatives like the 25AA040A series if applicable.

Memory IC Selection Notes

Select this component when a wide supply voltage range from 1.8V to 5.5V is required for compatibility with various logic levels. The 1 MHz clock speed suits applications where moderate data transfer rates are sufficient. Consider the 8-pin PDIP package for through-hole prototyping or legacy board designs. Evaluate the need for the HOLD pin functionality if bus sharing with other peripherals is necessary.

Memory IC Part Context

This part belongs to the 25XX040 family, which includes variants like the 25LC040 and 25C040. These devices share similar functional architectures but differ in operating voltage ranges and maximum clock frequencies. The 25AA040 specifically targets applications requiring operation down to 1.8V, distinguishing it from the 2.5V minimum 25LC040 and the 4.5V minimum 25C040.

Memory IC Replacement Considerations

Public confirmed substitute part numbers: 25AA040A-I/P

Memory IC FAQ

How does the HOLD pin function during serial communication?

The HOLD pin allows the host to pause transmission without resetting the sequence. When pulled low while SCK is low, the SI, SCK, and SO pins enter a high-impedance state. Communication resumes when HOLD is brought high while SCK is low.

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

Upon power-up, the device enters low-power Standby mode, and the write enable latch is automatically reset. A WREN instruction must be issued before any write operations can be completed.