Microchip Technology 24LC128-I/P

Overview

24LC128-I/P from Microchip Technology Inc. is a 128 Kbit (16K × 8) I²C-compatible serial EEPROM designed for nonvolatile data storage in low-power embedded systems. It operates from 2.5V to 5.5V, supports up to 400 kHz clock frequency, features hardware write-protection via the WP pin, and delivers 1 million erase/write cycles with >200 years of data retention. It is used in industrial sensor calibration storage and configuration backup in programmable logic controllers.

For engineers reviewing the 24LC128-I/P datasheet, 24LC128-I/P pinout, 24LC128-I/P application, or 24LC128-I/P equivalent, this page provides verified electrical parameters, package-specific pin mapping for PDIP-8, real-world I²C timing constraints, and validated alternative parts for design continuity and supply chain resilience.

Technical Context

The 24LC128-I/P implements a two-wire I²C interface with Schmitt-trigger inputs on SDA and SCL for noise immunity, slope-controlled outputs to suppress ground bounce, and a 64-byte page write buffer enabling efficient bulk writes. Its address decoding uses A0–A2 pins to support up to eight devices on a single bus (two for MSOP).

Internally, it employs a self-timed erase/write cycle with automatic page boundary handling, acknowledge polling for write completion detection, and a 1 µA max standby current at I-temp (−40°C to +85°C). The device does not generate ACK during internal write cycles, requiring software-level polling for synchronization.

Key Specifications

Pinout & Package

24LC128-I/P is supplied in an 8-lead PDIP (Plastic Dual In-line Package) with 0.300-inch body width, lead pitch of 0.100 inch, and through-hole mounting. Pin 1 is marked with a notch or dot; orientation follows standard DIP numbering (counterclockwise from top-left corner).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA128-I/P, the 24LC128-I/P offers higher minimum VCC (2.5V vs. 1.7V) but identical timing, packaging, and feature set for 3.3V/5V systems; versus AT24C128N-10PU-2.7, it provides hardware write protection and guaranteed pin compatibility, reducing qualification risk in industrial deployments.

Availability

24LC128-I/P is available at Aetrix Electronics and suitable for industrial sensor calibration storage, PLC configuration backup, and medical device settings retention requiring stable component supply across extended product lifecycles.

Supply support for 24LC128-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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and memory products, with global manufacturing and quality certifications including ISO 9001 and AEC-Q100.

The 24LC128-I/P belongs to Microchip's 24XX128 family of I²C serial EEPROMs, engineered for robustness in industrial and automotive environments where data integrity, long-term retention, and noise-immune communication are critical.

FAQ

What is the maximum I²C clock frequency supported by the 24LC128-I/P?

The 24LC128-I/P supports up to 400 kHz when VCC is 2.5V or higher. At VCC < 2.5V, the maximum clock frequency drops to 100 kHz. This dual-speed capability ensures reliable operation across both standard 3.3V/5V systems and lower-voltage designs, while maintaining full I²C protocol compliance. The 24LC128-I/P does not support 1 MHz operation - that capability is exclusive to the 24FC128 variant.

Does the 24LC128-I/P have hardware write protection, and how is it implemented?

Yes, the 24LC128-I/P includes a dedicated Write-Protect (WP) pin. When WP is tied to VCC, all write operations (byte and page) are inhibited while read operations remain fully functional. When WP is tied to VSS, full read/write access is enabled. The WP state is sampled at the Stop bit of each write command, making it effective for preventing accidental writes during power transitions or firmware errors.

How many devices can be connected on the same I²C bus using the 24LC128-I/P?

Up to eight 24LC128-I/P devices can be connected on a single I²C bus using the A0, A1, and A2 address pins to configure unique 3-bit chip addresses (0x50–0x57). Each pin must be hardwired to either VCC or VSS. This enables scalable memory expansion - for example, eight devices provide 1 Mbit of contiguous address space - without requiring additional I²C buses or multiplexers.

What is the page write buffer size of the 24LC128-I/P, and why does it matter?

The 24LC128-I/P has a 64-byte page write buffer. This means up to 64 bytes can be written in a single I²C transaction, significantly reducing bus overhead compared to individual byte writes. For firmware update routines or sensor calibration table uploads, this cuts required I²C start/stop sequences by 64×, improving efficiency and minimizing bus contention in multi-master systems.

Is the 24LC128-I/P RoHS compliant and qualified for industrial temperature operation?

Yes, the 24LC128-I/P is RoHS compliant and rated for Industrial temperature range (−40°C to +85°C), as indicated by the "I" suffix in the part number. It meets AEC-Q100 stress testing requirements for automotive-grade reliability, making it suitable for harsh environments such as factory floors, outdoor metering, and transportation control systems where thermal stability and long-term data integrity are essential.