24AA256-E/SM

Memory IC Overview

The Microchip 24AA256-E/SM is a 32K x 8 (256-Kbit) serial EEPROM utilizing an I²C-compatible two-wire interface. It operates on a single supply voltage ranging from 1.7V to 5.5V and supports clock frequencies up to 400 kHz for voltages at or above 2.5V, with 100 kHz support below that threshold. The device features a 64-byte page write buffer, hardware write protection via the WP pin, and Schmitt trigger inputs for noise suppression. It offers over one million erase/write cycles and data retention exceeding 200 years within an industrial temperature range of -40°C to +85°C.

Memory IC Feature Summary

• Supports cascading up to eight devices on the same bus using hardware address pins A0, A1, and A2.
• Includes a 64-byte page write buffer to optimize write throughput.
• Features hardware write protection controlled by the WP pin to prevent accidental data modification.
• Incorporates Schmitt trigger inputs and output slope control for enhanced noise immunity and ground bounce elimination.

Memory IC Applications

• Personal communications equipment requiring low-power non-volatile storage
• Data acquisition systems needing reliable parameter retention
• Embedded controllers storing configuration settings

Memory IC Procurement Notes

Verify the specific suffix 'E' confirms the extended temperature grade (-40°C to +125°C) if required, as the 'I' grade covers -40°C to +85°C. Confirm the 'SM' suffix corresponds to the 8-lead MSOP package. Ensure the design accounts for the 1.7V minimum operating voltage for the 24AA256 series. Check RoHS compliance status for the specific manufacturing lot.

Memory IC Selection Notes

Select this component when a 256-Kbit capacity is needed with I²C connectivity. The 24AA256 variant supports operation down to 1.7V, unlike the 24LC256 which requires a minimum of 2.5V. The MSOP package is suitable for space-constrained surface-mount designs. Consider the 24FC256 if higher clock speeds up to 1 MHz are necessary.

Memory IC Part Context

This part belongs to the 24XX256 family of serial EEPROMs manufactured by Microchip Technology. The family includes the 24AA256, 24LC256, and 24FC256 variants, which share similar pinouts and protocols but differ in voltage ranges and maximum clock frequencies. The 24AA256 specifically targets applications requiring wide voltage operation starting from 1.7V.

Memory IC Replacement Considerations

The 24LC256-E/SM is a compatible alternative but requires a minimum supply voltage of 2.5V instead of 1.7V. The 24FC256-E/SM offers increased speed capabilities up to 1 MHz. Verify that the replacement package matches the 8-lead MSOP footprint and that the temperature grade meets system requirements.

Memory IC FAQ

How many devices can be connected to the same I²C bus?

Up to eight 24AA256 devices can be connected to the same bus by configuring the A0, A1, and A2 chip select pins to different logic levels.

What is the function of the WP pin?

The Write-Protect (WP) pin allows hardware protection of the memory array. When tied to VCC, write operations are inhibited, while read operations remain unaffected. Tying it to VSS enables writes.

Does the device support acknowledge polling?

Yes, the device does not generate acknowledge signals during an internal write cycle. This allows the host to perform acknowledge polling to determine when the write cycle is complete before issuing new commands.