24LC21T-I/SN

Memory IC Overview

The Microchip Technology 24LC21T-I/SN is a 1Kb (128 x 8) 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 interfaces with clock frequencies up to 400 kHz at 5V and 100 kHz at 2.5V. The device features dual-mode operation: Transmit-only mode for monitor identification via the VCLK pin, and Bidirectional mode for standard read/write access. It includes hardware write protection, a page-write buffer for up to 8 bytes, and ensures 1,000,000 erase/write cycles with data retention exceeding 200 years.

Memory IC Feature Summary

• Implements DDC1/DDC2 interface specifications for monitor identification
• Supports dual-mode operation including Transmit-only and Bidirectional protocols
• Features hardware write protection via the VCLK pin in Bidirectional mode
• Utilizes low-power CMOS technology with typical standby current of 10 µA

Memory IC Applications

• Monitor identification and configuration storage
• Industrial control systems requiring non-volatile memory
• Applications needing dual-mode serial data transmission

Memory IC Procurement Notes

Verify that the specific ordering suffix 'T' corresponds to tape-and-reel packaging as indicated by distributor listings, while confirming the base part number matches the SOIC-8 package. Ensure the Industrial temperature grade (-40°C to +85°C) aligns with system requirements. Note that this component is not recommended for new designs; confirm if the successor 24LCS21A is acceptable for the intended application before procurement.

Memory IC Selection Notes

Select this component when dual-mode functionality is required, specifically for applications utilizing the Transmit-only mode for display identification. Verify that the 8-byte page write buffer meets throughput needs. Consider the 24LCS21A as a modern alternative if the legacy Dual Mode I²C Serial EEPROM specification is not strictly necessary for the design.

Memory IC Part Context

The 24LC21 belongs to the 24LC21 family of 1Kb serial EEPROMs manufactured by Microchip Technology. It is designed for applications requiring storage and serial transmission of configuration information. The datasheet explicitly states it is not recommended for new designs, recommending the 24LCS21A instead.

Memory IC Replacement Considerations

Microchip recommends using the 24LCS21A as a replacement. Verify compatibility regarding pinout and electrical characteristics before substitution.