Microchip Technology 24LC128-E/MS

Overview

24LC128-E/MS from Microchip Technology is a 128 Kbit (16K × 8) I²C-compatible serial EEPROM with 2.5V–5.5V supply range, 400 kHz maximum clock frequency, and extended temperature operation (–40°C to +125°C). It features hardware write-protection via the WP pin, 64-byte page write buffer, and Schmitt-trigger inputs for noise immunity. It is used in automotive infotainment control modules for storing calibration data and configuration parameters.

For engineers reviewing the 24LC128-E/MS datasheet, 24LC128-E/MS pinout, 24LC128-E/MS application, or 24LC128-E/MS equivalent, this page delivers verified electrical specs, package mapping, I²C timing constraints, endurance metrics, and real-world use context - all confirmed against Microchip's DS20001191T datasheet and official packaging documentation.

Technical Context

The 24LC128-E/MS implements a two-wire I²C slave interface with fixed 7-bit address prefix '1010' and user-configurable A2/A1/A0 bits for up to eight device addressing on one bus. Its internal architecture includes a 64-byte page latch, HV generator for EEPROM programming, and memory control logic supporting byte and page writes with self-timed erase/write cycles.

It operates exclusively as a slave device synchronized to an external master's SCL clock, requiring open-drain SDA/SCL with pull-up resistors. Write protection is implemented via level-sensitive WP pin sampling at the Stop bit, and all I/O pins include Schmitt-trigger inputs and slope-controlled outputs to suppress ground bounce and EMI.

Key Specifications

Pinout & Package

24LC128-E/MS uses an 8-lead MSOP package (Microchip drawing code MS), with 3 mm × 3 mm body, 0.65 mm pitch, and exposed pad (optional VSS connection). Pins A0 and A1 are not connected in this package variant; only A2, VSS, SDA, SCL, WP, VCC are functional.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24LC128-E/MS, the 24AA128-I/MS offers lower-voltage flexibility but lacks extended temperature capability, while the AT24C128C-MAHM-T provides higher I²C speed and alternate supply chain access but omits AEC-Q100 validation and has longer write latency - making 24LC128-E/MS the optimal choice for thermally demanding, safety-critical automotive deployments.

Availability

24LC128-E/MS is available at Aetrix Electronics and suitable for automotive body control units, industrial PLCs, medical infusion pumps, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 24LC128-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 devices, and memory solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The 24LC128-E/MS belongs to Microchip's 24XX128 family of I²C EEPROMs, engineered specifically for automotive and industrial applications demanding AEC-Q100 qualification, extended temperature operation, and robust noise immunity in electrically harsh environments.

FAQ

What is the maximum I²C clock frequency supported by the 24LC128-E/MS?

The 24LC128-E/MS supports up to 400 kHz I²C clock frequency when VCC is 2.5V or higher. This is specified in Table 1-2 of DS20001191T and applies across its full –40°C to +125°C operating range. Below 2.5V, the device is not rated for operation; thus, 400 kHz is its absolute maximum validated speed. The 24LC128-E/MS does not support 1 MHz operation - that capability is exclusive to the 24FC128 variant.

Does the 24LC128-E/MS have AEC-Q100 qualification?

Yes, the 24LC128-E/MS is explicitly AEC-Q100 qualified for Grade 1 (–40°C to +125°C), as stated in the "Temperature Ranges" section of the Device Selection Table in DS20001191T. This qualification covers stress testing for temperature cycling, HTOL, ESD, and other automotive reliability requirements - confirming its suitability for under-hood and body-control applications.

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

Up to two 24LC128-E/MS devices can share one I²C bus. This limitation arises because the MSOP package has no-connect A0 and A1 pins, leaving only A2 as the configurable chip-select bit. With A2 = 0 or 1, exactly two unique 7-bit slave addresses (1010_0xx and 1010_1xx) are possible. The datasheet confirms this in Section 2.1 and Figure 5-1 for MSOP variants.

What is the write-protect behavior of the 24LC128-E/MS WP pin?

The WP pin on the 24LC128-E/MS is sampled only at the Stop condition edge of each write command. When tied to VCC, it inhibits all write operations (byte and page) while allowing unrestricted reads; when tied to VSS, writes are fully enabled. Critically, toggling WP during an ongoing write cycle has no effect - protection state is latched once per command, ensuring deterministic behavior during power transitions.

What is the page write buffer size and maximum write time for the 24LC128-E/MS?

The 24LC128-E/MS features a 64-byte page write buffer, enabling burst writes within a single physical page boundary (addresses aligned to 0x00–0x3F, 0x40–0x7F, etc.). Its maximum write cycle time is 5 ms for both byte and page writes, as specified in Parameter TWC (Table 1-2). This fixed latency applies regardless of data count - writing 1 byte or 64 bytes takes the same 5 ms internal programming time.