24AA256UID-I/P

Memory IC Overview

The Microchip Technology 24AA256UID-I/P is a 32K x 8 (256 Kbit) Serial Electrically Erasable PROM featuring preprogrammed EUI-48 and EUI-64 node addresses and a 32-bit Unique ID. It operates across a broad voltage range of 1.7V to 5.5V with a maximum clock frequency of 400 kHz. The device utilizes a 2-wire I2C compatible interface and supports page writes up to 64 bytes. It is housed in an 8-lead PDIP package and functions within an industrial temperature range of -40°C to +85°C.

Memory IC Feature Summary

• Preprogrammed globally unique 48-bit or 64-bit node addresses compatible with EUI standards
• Factory programmed 32-bit serial number stored in permanently write-protected memory
• Low-power CMOS technology with standby current as low as 100 nA typical
• Schmitt trigger inputs for noise suppression and output slope control to eliminate ground bounce

Memory IC Applications

• Personal communications devices requiring unique identification
• Data acquisition systems needing persistent storage with addressability
• Network nodes requiring IEEE compliant addressing
• Embedded systems utilizing cascaded I2C bus architectures

Memory IC Procurement Notes

Verify the specific suffix 'I/P' corresponds to the Industrial temperature range (-40°C to +85°C) and 8-lead PDIP package. Confirm that the UID variant includes factory-programmed EUI-48/EUI-64 addresses, distinguishing it from standard 24AA256 models. Ensure application designs account for the permanent write protection of the upper array section containing these identifiers.

Memory IC Selection Notes

Select this component when unique hardware identification via EUI standards is required alongside standard EEPROM functionality. The 24AA256UID provides a scalable solution for applications needing up to 2 Mbit contiguous address space through cascading. Consider the 1.7V minimum operating voltage for low-power designs. Verify that the 400 kHz clock speed meets system timing requirements at the selected supply voltage.

Memory IC Part Context

This part belongs to the Microchip 24AA256 series of 256K I2C Serial EEPROMs. The UID suffix specifically denotes devices with preprogrammed unique identifiers. Other variants in the family include standard EEPROMs without UID features or different package options like SOIC and TSSOP. The series shares common electrical characteristics but differs in factory programming and physical packaging.

Memory IC Replacement Considerations

Direct replacements must match the 24AA256UID specifications, including the preprogrammed EUI addresses. Standard 24AA256 parts lack the UID feature and are not functionally equivalent for identification purposes. Alternative packages such as 24AA256UID-I/SN or 24AA256UIDT-I/ST offer surface mount options with identical electrical and functional properties.

Memory IC FAQ

Is the preprogrammed serial number writable?

No, the 32-bit serial number, along with the EUI-48 and EUI-64 addresses, is stored in the upper eighth of the EEPROM array which is permanently write-protected.

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

Up to eight 24AA256UID devices can be connected to the same bus using the A0, A1, and A2 chip select pins to expand the address space.

What is the write cycle time for this device?

The self-timed erase/write cycle time is a maximum of 5 ms per byte or page write operation.