Microchip Technology 24LC128T-I/SMG

Overview

24LC128T-I/SMG 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 I²C clock frequency, features hardware write-protection via the WP pin, and delivers 1 µA max standby current at industrial temperature range (–40°C to +85°C). It is commonly used in set-top boxes for configuration parameter retention.

For engineers reviewing the 24LC128T-I/SMG datasheet, 24LC128T-I/SMG pinout, 24LC128T-I/SMG application, or 24LC128T-I/SMG equivalent, this page provides verified electrical specs, package mapping to 8-lead SOIC (SM), functional pin roles, real-world use cases, and two confirmed alternative parts with documented technical and application differences.

Technical Context

The 24LC128T-I/SMG 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 cascading support for up to eight devices on one bus using A0–A2 address pins. Its internal architecture includes a 64-byte page write buffer, self-timed erase/write cycle, and an address pointer that auto-increments during sequential reads.

It uses CMOS EEPROM technology with >1 million erase/write cycles and >200 years of data retention. The device samples the WP pin at the Stop bit to enable or disable writes, and supports acknowledge polling to detect write completion without fixed timing delays.

Key Specifications

Pinout & Package

24LC128T-I/SMG is packaged in an 8-lead SOIC (SM) - narrow-body, 3.90 mm width, RoHS-compliant matte tin finish. Pin 1 is marked with a beveled corner or dot; orientation follows JEDEC MS-012 standard.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA128T-I/SM and AT24C128N-10SU-2.7, the 24LC128T-I/SMG offers guaranteed 2.5V operation and integrated hardware write protection - making it the preferred choice for industrial designs requiring deterministic voltage margins and physical write security.

Availability

24LC128T-I/SMG is available at Aetrix Electronics and suitable for industrial sensor nodes, medical device calibration storage, and smart energy metering requiring stable component supply across extended product lifecycles.

Supply support for 24LC128T-I/SMG 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 devices, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing infrastructure.

The 24LC128 belongs to Microchip's 24XX128 family of I²C EEPROMs, engineered specifically for reliable, low-power nonvolatile storage in industrial, medical, and automotive applications demanding long data retention and robust noise immunity.

FAQ

What is the minimum VCC voltage required for reliable operation of the 24LC128T-I/SMG?

The 24LC128T-I/SMG requires a minimum VCC of 2.5V for guaranteed operation across its full industrial temperature range (–40°C to +85°C). Below 2.5V, functionality is not assured - unlike the 24AA128 variant, which supports down to 1.7V. This 2.5V floor ensures stable internal charge pump performance during write cycles and reliable I²C communication timing.

Does the 24LC128T-I/SMG support 1 MHz I²C clock frequency?

No, the 24LC128T-I/SMG does not support 1 MHz I²C operation. Its maximum clock frequency is 400 kHz across the full 2.5V–5.5V VCC range. Only the 24FC128 variant in the same family supports 1 MHz - the 24LC128T-I/SMG's timing specifications, including THIGH, TLOW, and TR, are validated only up to 400 kHz.

How many devices can be connected on a single I²C bus using the 24LC128T-I/SMG?

Up to eight 24LC128T-I/SMG devices can be connected on a single I²C bus using the A0, A1, and A2 address pins to configure unique 3-bit chip addresses. Each pin must be hardwired to VCC or VSS; floating connections are not permitted. For the SOIC (SM) package used in 24LC128T-I/SMG, all three address pins are functional and electrically connected.

What happens when the WP pin is tied to VCC on the 24LC128T-I/SMG?

When the WP pin is tied to VCC on the 24LC128T-I/SMG, all write operations - including byte writes, page writes, and write commands - are inhibited. Read operations remain fully functional. The device acknowledges write commands but performs no internal programming; the WP state is sampled at the Stop bit of each command, ensuring deterministic protection even during partial bus transactions.

Is the 24LC128T-I/SMG qualified for automotive applications?

The 24LC128T-I/SMG is rated for Industrial temperature range (–40°C to +85°C) and is not AEC-Q100 qualified. While the broader 24XX128 family includes AEC-Q100 variants (e.g., 24LC128-E/SM for Extended temp), the "I" suffix in 24LC128T-I/SMG explicitly denotes Industrial grade - suitable for industrial controls and medical equipment, but not for under-hood automotive use without additional qualification.