24LC22A-I/P

Memory IC Overview

The Microchip Technology 24LC22A-I/P is a 2Kbit (256 x 8-bit) dual-mode serial EEPROM housed in an 8-pin PDIP 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. Designed for industrial applications, it functions reliably within a 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 standard I2C read/write access.
• Integrated write protection mechanism utilizing the VCLK pin to enable or disable programming capabilities during bidirectional operations.
• Compliance with DDC1 and DDC2 standards, including support for Enhanced EDID specifications for monitor identification.
• High noise immunity provided by Schmitt Trigger inputs and internal spike suppression filters on all communication pins.

Memory IC Applications

• Storing and transmitting Extended Display Identification Data (EDID) for computer monitors and displays.
• Configuration and control information storage in systems requiring serial transmission protocols.
• Monitor identification circuits implementing DDC1 or DDC2 interface standards.
• Applications requiring non-volatile memory with specific power-up initialization sequences.

Memory IC Procurement Notes

Verify that the component matches the exact 24LC22A-I/P designation to ensure correct Industrial temperature rating and PDIP packaging. Confirm datasheet revision DS21683B aligns with your design requirements. Check for RoHS compliance status as specified in the manufacturer documentation. Ensure supply chain sources provide authentic Microchip products to avoid counterfeit risks.

Memory IC Selection Notes

Select this component when dual-mode functionality is required for display applications. Choose this part if the design necessitates a hardware-based transition between EDID streaming and standard I2C communication. Consider the 8-pin PDIP package for through-hole mounting constraints. Verify that the system voltage falls within the 2.5V to 5.5V operating range for optimal performance.

Memory IC Part Context

The 24LC22A belongs to Microchip's 24LC series of serial EEPROMs. It is specifically engineered for video and display applications where compatibility with VESA Display Data Channel standards is critical. The device integrates high-voltage generators and error detection logic typical of the family while offering unique dual-mode capabilities not found in standard EEPROMs.

Memory IC Replacement Considerations

Direct replacements include other 24LC22A variants such as the SOIC package version 24LC22A-I/SN. Cross-family substitutes like the 24AA024 may share similar capacities but lack the specific dual-mode DDC functionality. Verify pinout and electrical characteristics before substituting any alternative components.

Memory IC FAQ

How does the device switch between Transmit-Only and Bidirectional modes?

The device powers up in Transmit-Only mode. A valid high-to-low transition on the SCL pin triggers a transition to Bidirectional mode. If no valid I2C control byte is detected after 128 VCLK pulses, it reverts to Transmit-Only mode.

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

In Bidirectional mode, the VCLK pin serves as a write-protection control. Holding VCLK high enables normal write operations, while holding it low prevents writing to the memory array.

Can the 24LC22A be used as a standard ROM?

Yes, by connecting the VCLK pin to VSS, the device can operate as a serial ROM in Bidirectional mode, although this configuration disables the Transmit-Only mode capability.