Microchip Technology 24FC128-I/MS

Overview

24FC128-I/MS from Microchip Technology Inc. is a 128 Kbit (16K × 8) I²C-compatible serial EEPROM designed for low-voltage embedded systems. It operates from 1.7V to 5.5V, supports up to 1 MHz I²C clock frequency at VCC ≥ 2.5V, features hardware write-protection via the WP pin, and delivers 64-byte page write capability with ≤5 ms self-timed write cycle - deployed in industrial sensor nodes and firmware configuration storage.

For engineers reviewing the 24FC128-I/MS datasheet, 24FC128-I/MS pinout, 24FC128-I/MS application, or 24FC128-I/MS equivalent, key selection criteria include its 1 MHz I²C speed at 2.5–5.5V, industrial temperature range (−40°C to +85°C), MSOP-8 package footprint, and hardware write-protect functionality for secure parameter retention.

Technical Context

The 24FC128-I/MS implements a two-wire I²C interface with Schmitt-trigger inputs on SDA/SCL for noise immunity and slope-controlled outputs to suppress ground bounce. Its internal address counter enables sequential reads across the full 128Kbit memory space, while cascading support for up to eight devices (two for MSOP due to unconnected A0/A1 pins) allows scalable memory expansion.

It uses CMOS EEPROM technology with a dedicated 64-byte page latch, self-timed erase/write cycles, and a high-voltage generator for cell programming. Write protection is enforced by sampling the WP pin state at the Stop bit of each write command - no write occurs if WP = VCC, but read operations remain fully functional.

Key Specifications

Pinout & Package

24FC128-I/MS is packaged in an 8-lead MSOP (Micro Small Outline Package) with 0.65 mm lead pitch and exposed pad (optional VSS connection). Pin A0 and A1 are not connected per datasheet Note on page 7 - 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 24AA128-I/MS and AT24C128-MAHM-T, the 24FC128-I/MS uniquely delivers guaranteed 1 MHz operation down to 2.5V while maintaining full compatibility with 1.7V systems - making it optimal for high-throughput, low-voltage embedded NVM where speed and voltage flexibility are jointly critical.

Availability

24FC128-I/MS is available at Aetrix Electronics and suitable for industrial sensor calibration, medical device configuration, automotive body control modules, and IoT edge node firmware settings requiring stable component supply across extended production lifecycles.

Supply support for 24FC128-I/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 U.S.-based semiconductor company specializing in microcontrollers, analog devices, and memory solutions for embedded control applications.

The 24FC128 belongs to Microchip's 24XX128 family of I²C EEPROMs engineered for reliable, low-power nonvolatile storage in resource-constrained industrial and automotive systems.

FAQ

What is the maximum I²C clock frequency supported by the 24FC128-I/MS?

The 24FC128-I/MS supports up to 1 MHz I²C clock frequency when VCC is 2.5V or higher. At VCC < 2.5V, the maximum clock frequency drops to 400 kHz. This dual-speed capability ensures compatibility with both legacy 400 kHz systems and high-throughput designs requiring faster configuration writes - a key differentiator from the 24AA128-I/MS, which is limited to 400 kHz across its entire voltage range. The 24FC128-I/MS maintains full electrical compliance at 1 MHz per Table 1-2 of DS20001191T.

Does the 24FC128-I/MS support hardware write-protection, and how is it implemented?

Yes, the 24FC128-I/MS implements hardware write-protection via the WP (Write-Protect) pin. When WP is tied to VCC, all write operations to the EEPROM array are inhibited - including byte and page writes - while read operations remain fully functional. The WP state is sampled at the Stop bit of each write command, ensuring protection is enforced at the protocol level. This feature is critical for safeguarding calibration data or security keys in the 24FC128-I/MS against accidental or malicious overwrites during power transitions.

What is the memory organization and page structure of the 24FC128-I/MS?

The 24FC128-I/MS contains 128 Kbit (16,384 × 8-bit) of EEPROM organized into 256 pages of 64 bytes each. Page boundaries align at addresses 0x0000, 0x0040, 0x0080, etc. Page writes must remain within a single physical page - crossing a boundary causes wraparound within that page. This architecture enables efficient burst writes while requiring firmware to manage address alignment, a constraint explicitly documented in Section 6.3 of the 24FC128-I/MS datasheet DS20001191T.

Is the 24FC128-I/MS qualified for automotive applications?

The 24FC128-I/MS is specified for Industrial temperature range (−40°C to +85°C) and is not AEC-Q100 qualified. While the broader 24XX128 family includes AEC-Q100 qualified variants (e.g., 24LC128-E/P), the 24FC128-I/MS part number itself carries the 'I' suffix denoting Industrial grade only. For automotive body control or infotainment modules requiring AEC-Q100 compliance, engineers must select a designated automotive-grade variant - the 24FC128-I/MS is intended for industrial, medical, and commercial applications where extended temperature qualification is not mandated.

How does the 24FC128-I/MS handle I²C bus arbitration and noise immunity?

The 24FC128-I/MS incorporates Schmitt-trigger inputs on both SDA and SCL pins with 50 ns input filter spike suppression and hysteresis of 0.05 × VCC - significantly improving noise immunity in electrically harsh environments. Its open-drain I²C interface follows standard bus arbitration rules: multiple masters can share the bus, and collision detection relies on wired-AND behavior. The device does not initiate arbitration but responds correctly as a slave under multi-master protocols defined in Section 4 of DS20001191T, ensuring robust interoperability in complex embedded systems using the 24FC128-I/MS.