Microchip Technology 24LCS22A-I/P

Overview

24LCS22A-I/P from Microchip Technology Inc. is a 2 Kbit dual-mode serial EEPROM designed for display configuration storage in VESA-compliant systems. It operates in Transmit-Only mode (1 Kbit, DDC1™) and Bidirectional mode (2 Kbit, I²C™), supports 2.5–5.5V supply, features hardware write-protection via WP pin and VCLK-level control, and delivers 1 mA active current with 10 μA standby current - enabling reliable EDID™ data transmission in monitor and graphics subsystems.

For engineers reviewing the 24LCS22A-I/P datasheet, 24LCS22A-I/P pinout, 24LCS22A-I/P application, or 24LCS22A-I/P equivalent, key selection considerations include its dual-clock architecture (VCLK for DDC1™ transmit, SCL for I²C™ bidirectional access), flexible write-protection logic (WP fuse + VCLK high/low), 1M endurance cycles, >200-year data retention, and compatibility with industrial temperature range (−40°C to +85°C) in PDIP package.

Technical Context

The 24LCS22A-I/P implements two independent serial protocols on shared SDA: a unidirectional DDC1™ mode clocked by VCLK (for continuous EDID™ streaming), and a bidirectional I²C™ mode clocked by SCL (for full 2K memory read/write). Mode transition occurs only on valid SCL edge followed by detection of slave address 1010000X - and once in Bidirectional mode, power cycle is required to return to Transmit-Only mode.

Its internal architecture includes a programmable write-protection fuse (enabled by writing to address 7Fh), Schmitt-trigger inputs on SDA/SCL/VCLK for noise immunity, VCC threshold detector disabling writes below 1.5V, and page-write buffer supporting up to eight bytes per self-timed write cycle (max 10 ms). The device complies fully with VESA E-EDID™ 1.3 and DDC2™ standards but excludes Access.bus™ capability.

Key Specifications

Pinout & Package

8-pin PDIP (Plastic Dual In-line Package), 300-mil width, through-hole mounting. RoHS-compliant matte tin lead finish. Pin 1 marked with dot or notch orientation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar serial EEPROM applications.

Compared with AT24C02C-SSHM-T and M24C02-RMN6TP, the 24LCS22A-I/P uniquely integrates VESA-certified DDC1™ streaming and I²C™ bidirectional access in one device - eliminating external glue logic, reducing PCB area, and guaranteeing interoperability with standard graphics drivers without firmware modification.

Availability

24LCS22A-I/P is available at Aetrix Electronics and suitable for monitor manufacturing, graphics card design, and industrial HMI development requiring stable component supply, long-term lifecycle assurance, and VESA-compliant EDID™ implementation.

Supply support for 24LCS22A-I/P includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Microchip Technology Inc. is a leading provider of microcontrollers, analog components, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 24LCS22A-I/P belongs to Microchip's VESA-optimized serial EEPROM product line, engineered specifically for display interface compliance - delivering integrated DDC1™/DDC2™ functionality, industrial temperature resilience, and robust write-protection for monitor and graphics subsystems.

FAQ

What is the primary function of the VCLK pin on the 24LCS22A-I/P?

The VCLK pin serves two distinct roles: in Transmit-Only mode, it acts as the bit-clock input for DDC1™ EDID™ streaming (data output on rising edge); in Bidirectional mode, it functions as a write-enable control - writes are permitted only when VCLK is held high. This dual role is fundamental to the 24LCS22A-I/P's VESA compliance and cannot be replicated by standard I²C™ EEPROMs.

How does the 24LCS22A-I/P enter Bidirectional mode from Transmit-Only mode?

The 24LCS22A-I/P enters Bidirectional mode only upon detecting a valid high-to-low transition on the SCL pin, followed immediately by recognition of its I²C™ slave address (1010000X) on the bus. If no valid address is received within 128 VCLK pulses, it automatically reverts to Transmit-Only mode. Power cycling is the sole method to force a return to Transmit-Only mode once Bidirectional mode is entered.

Can the 24LCS22A-I/P be used as a drop-in replacement for standard 2K I²C™ EEPROMs like the 24LC02B?

No - the 24LCS22A-I/P is not a drop-in replacement for generic 2K I²C™ EEPROMs. It requires VCLK pin connection and implements unique dual-mode protocol handling. While it responds to standard I²C™ commands in Bidirectional mode, its Transmit-Only mode, VCLK-dependent write enable, and E-EDID™-specific initialization sequence make direct substitution incompatible without hardware and firmware redesign.

What happens if the WP pin is left unconnected on the 24LCS22A-I/P?

If the WP pin is left unconnected (open), and the write-protection fuse has not been set (i.e., address 7Fh has never been written), the 24LCS22A-I/P remains fully writable in Bidirectional mode whenever VCLK is high. However, once the fuse is set, an open WP pin defaults to logic high per Table 6-1, resulting in read-only operation regardless of VCLK state - so intentional floating of WP is not recommended in production designs.

Does the 24LCS22A-I/P support page write operations, and what is the page size?

Yes, the 24LCS22A-I/P supports page write operations with an 8-byte page buffer. Up to eight bytes can be loaded into the buffer before issuing a Stop condition, after which all bytes are written simultaneously in a self-timed cycle (≤10 ms). Physical page boundaries align to 8-byte intervals (addresses 00h–07h, 08h–0Fh, etc.), and crossing a boundary causes wraparound within the current page - requiring software to manage alignment.