24LC22AT-I/SN

Memory IC Overview

The Microchip Technology 24LC22AT-I/SN is a 2Kbit (256 x 8) dual-mode serial EEPROM housed in an 8-pin SOIC package. It operates on a single supply voltage ranging from 2.5V to 5.5V and supports I2C-compatible 2-wire serial interfaces with clock frequencies up to 100 kHz at 2.5V and 400 kHz at 5V. The device features a page-write buffer for eight bytes, self-timed write cycles of 10 ms, and data retention exceeding 200 years. It includes ESD protection greater than 4000V and operates within an industrial temperature range of -40°C to +85°C.

Memory IC Feature Summary

• Dual-mode operation supporting both Transmit-Only mode for continuous EDID streaming and Bidirectional mode for full read/write access via the I2C bus.
• Implements DDC1/DDC2 interface standards for monitor identification, including automatic recovery to DDC1 mode upon loss of SCL synchronization.
• Integrated write protection mechanism where holding the VCLK pin low prevents programming operations while maintaining read capability.

Memory IC Applications

• Enhanced EDID storage for display monitors requiring compliance with VESA standards.
• Configuration and control information storage in systems utilizing serial transmission protocols.
• Applications requiring robust monitor identification through DDC1 or DDC2 communication channels.

Memory IC Procurement Notes

Verify that the specific ordering suffix 'T' corresponds to tape-and-reel packaging if required by automated assembly processes, as standard variants may utilize tube packaging. Confirm the 'I' suffix indicates the industrial temperature grade (-40°C to +85°C). Ensure the SOIC package width matches the design footprint requirements. Cross-reference the datasheet revision to confirm compatibility with current manufacturing specifications.

Memory IC Selection Notes

Select this component when dual-mode functionality is necessary to support both legacy DDC1 timing and modern I2C bidirectional communication. It is suitable for designs requiring write protection via the VCLK pin rather than hardware pins. Consider the 8-byte page buffer size for write optimization. Verify that the system power supply remains stable above 1.5V to ensure internal logic integrity during noise events.

Memory IC Part Context

This device belongs to the 24LC22A family of serial EEPROMs designed specifically for display data channel applications. Unlike standard EEPROMs, it incorporates specialized logic to handle VESA DDC protocols. The 'SN' designation identifies the surface-mount SOIC package variant, distinguishing it from through-hole PDIP options within the same electrical specification family.

Memory IC Replacement Considerations

Direct substitutes include other 24LC22A variants with different package styles such as 24LC22A-I/P for through-hole mounting. Devices lacking dual-mode capabilities cannot replace this part in DDC applications. Ensure any replacement maintains the 2.5V to 5.5V operating range and I2C compatibility.

Memory IC FAQ

How does the device transition between modes?

The device powers up in Transmit-Only mode. A high-to-low transition on the SCL pin triggers a transition state where it searches for a valid I2C control byte. If detected, it switches permanently to Bidirectional mode until power is removed.

What is the function of the VCLK pin in Bidirectional mode?

In Bidirectional mode, VCLK serves as a write-enable control. Holding VCLK high allows normal write operations, while holding it low prevents any writes to the memory array, effectively acting as a software-controlled write protect.