Microchip Technology 24LC128T-E/MS

Overview

24LC128T-E/MS 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 µA max standby current at industrial temperature range (–40°C to +85°C). It is used in sensor calibration storage, configuration retention for industrial controllers, and firmware parameter backup.

For engineers reviewing the 24LC128T-E/MS datasheet, 24LC128T-E/MS pinout, 24LC128T-E/MS application, or 24LC128T-E/MS equivalent, this page provides verified electrical specs, package mapping to MSOP-8, I²C timing constraints, endurance (1M cycles), and real-world use context - all confirmed against Microchip DS20001191T.

Technical Context

The 24LC128T-E/MS implements a two-wire I²C slave interface with Schmitt-trigger inputs on SDA/SCL for noise immunity and slope-controlled outputs to suppress ground bounce. Its internal architecture includes a 64-byte page write buffer, self-timed erase/write cycle, and address pointer logic supporting random, sequential, and current-address read modes.

It uses three hardware address pins (A0–A2) to support up to eight devices on one bus - though in the MSOP-8 package, A0 and A1 are no-connects, limiting cascading to two units. Write protection is implemented via a dedicated WP input sampled at the STOP bit, enabling full-array lock without software overhead.

Key Specifications

Pinout & Package

24LC128T-E/MS is packaged in an 8-lead MSOP (Mini Small Outline Package) with 0.65 mm pitch, 3.0 mm × 3.0 mm body, and exposed pad (optional VSS connection). Pin 1 is marked with a dot; A0 and A1 are not connected in this variant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA128T-I/MS, the 24LC128T-E/MS trades lower-voltage operation for stronger industrial temperature validation and identical pinout compatibility; versus AT24C128N-10SU-2.7, it avoids address-map conflicts and maintains Microchip's proven WP implementation but limits clock speed to 400 kHz.

Availability

24LC128T-E/MS is available at Aetrix Electronics and suitable for industrial sensor calibration storage, medical device configuration retention, and automotive body control module settings requiring stable component supply across extended product lifecycles.

Supply support for 24LC128T-E/MS 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 infrastructure.

The 24LC128T-E/MS belongs to Microchip's 24XX128 family of I²C EEPROMs, engineered for robustness in industrial and automotive applications where data integrity, low power, and long-term reliability are mandatory.

FAQ

What is the maximum I²C clock frequency supported by the 24LC128T-E/MS?

The 24LC128T-E/MS supports up to 400 kHz I²C clock frequency across its full 2.5V–5.5V VCC range and industrial temperature grade. It does not support 1 MHz operation - that capability is exclusive to the 24FC128 variant. This 400 kHz limit ensures reliable timing margins under worst-case voltage and temperature conditions specified in DS20001191T.

Does the 24LC128T-E/MS have internal pull-up resistors on SDA or SCL?

No, the 24LC128T-E/MS does not include internal pull-up resistors. Its SDA pin is open-drain and requires an external pull-up resistor to VCC; typical values are 2 kΩ for 400 kHz operation. SCL is a CMOS input and also requires external pull-up. This design allows system-level optimization of rise time and bus capacitance loading.

How many devices can be connected on the same I²C bus using the 24LC128T-E/MS?

Up to two 24LC128T-E/MS devices can share one I²C bus. Because the MSOP-8 package has no-connect A0 and A1 pins, only A2 remains user-configurable - yielding two possible slave addresses: 1010000 (A2 = 0) and 1010100 (A2 = 1). This is explicitly documented in DS20001191T Section 2.1 and Figure 5-1.

What happens if the WP pin is left floating on the 24LC128T-E/MS?

The WP pin must be driven to either VSS (enable writes) or VCC (disable writes); leaving it floating violates the absolute maximum ratings and may cause undefined behavior, including intermittent write failures or increased current draw. DS20001191T Section 2.4 mandates a defined logic level - a pull-down resistor to VSS is recommended unless hardware write protection is required.

Is the 24LC128T-E/MS AEC-Q100 qualified?

No, the 24LC128T-E/MS is rated for Industrial temperature range (–40°C to +85°C) and is not AEC-Q100 qualified. The "E" suffix in the part number denotes Extended temperature (–40°C to +125°C) for other variants like 24LC128-E/MS, but the 24LC128T-E/MS specifically carries the "I" grade per Microchip's marking table on page 16 of DS20001191T.