Microchip Technology 24FC128-I/P

Overview

24FC128-I/P from Microchip Technology Inc. is a 128 Kbit (16K × 8) I²C-compatible serial EEPROM with 1 MHz maximum clock frequency at V_CC ≥ 2.5V, 1.7V–5.5V supply range, and industrial temperature rating (–40°C to +85°C). It features 64-byte page write buffer, hardware write-protect (WP), and Schmitt-trigger inputs for noise immunity - deployed in embedded system configuration storage, sensor calibration data retention, and firmware parameter backup.

For engineers reviewing the 24FC128-I/P datasheet, 24FC128-I/P pinout, 24FC128-I/P application, or 24FC128-I/P equivalent, this page delivers verified electrical specs, package mapping to 8-Lead PDIP, functional pin roles, real-world use cases, and two validated alternative parts with documented technical and application-level differences.

Technical Context

The 24FC128-I/P implements a two-wire I²C slave interface with fixed 4-bit control code (1010b) and user-configurable A0–A2 address bits enabling up to eight devices on one bus. Its internal architecture includes a 64-byte page latch, self-timed erase/write cycle, and HV generator for EEPROM programming.

It supports byte and page write modes, current/random/sequential read operations, and acknowledge polling for write-cycle completion detection. Write protection is controlled solely by the WP pin state (VSS = enabled, VCC = inhibited), sampled at the Stop bit of each write command.

Key Specifications

Pinout & Package

24FC128-I/P is supplied in an 8-Lead Plastic Dual In-line Package (PDIP), 300 mil body width, with standard through-hole mounting. Pin 1 is top-left corner when notch faces upward.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA128-I/P and AT24C128-10PU-2.7, the 24FC128-I/P uniquely delivers 1 MHz I²C performance within the same 1.7V–5.5V envelope and industrial temperature grade - making it optimal for time-sensitive embedded boot sequences and high-throughput parameter updates.

Availability

24FC128-I/P is available at Aetrix Electronics and suitable for industrial sensor calibration storage, medical device configuration backup, and automotive body control module settings requiring stable component supply across extended product lifecycles.

Supply support for 24FC128-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 manufacturer specializing in microcontrollers, analog devices, and memory products for embedded control applications.

The 24FC128 belongs to Microchip's 24XX128 family of I²C EEPROMs, designed specifically for reliable, low-voltage, high-endurance nonvolatile data storage in resource-constrained embedded systems.

FAQ

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

The 24FC128-I/P supports up to 1 MHz I²C clock frequency when V_CC is 2.5V or higher. At V_CC < 2.5V, the maximum clock rate drops to 400 kHz. This dual-speed capability allows seamless integration across 1.8V, 2.5V, 3.3V, and 5V system designs without sacrificing performance where voltage permits - a key differentiator versus 24AA128-I/P and 24LC128-I/P variants.

Does the 24FC128-I/P require external pull-up resistors on SDA and SCL lines?

Yes, the 24FC128-I/P requires external pull-up resistors on both SDA and SCL lines because its I²C interface uses open-drain outputs. For 1 MHz operation, a 2 kΩ pull-up to V_CC is recommended; for 400 kHz, 2.2 kΩ is typical. The device's Schmitt-trigger inputs ensure clean signal transitions even with these values, eliminating need for additional filtering components in most layouts.

How does hardware write-protection work on the 24FC128-I/P?

The WP pin on the 24FC128-I/P provides hardware-level write inhibition: when tied to V_CC, all write operations (byte and page) are blocked while read access remains fully functional. The pin is sampled at the Stop bit of each write command, so toggling WP mid-cycle has no effect. This enables fail-safe configuration locking during power-up sequences or critical runtime states without firmware dependency.

What is the page write buffer size of the 24FC128-I/P, and why does it matter?

The 24FC128-I/P features a 64-byte page write buffer. This allows up to 64 bytes to be loaded into the buffer and written to memory in a single self-timed cycle - significantly reducing I²C bus occupancy versus individual byte writes. For example, writing 64 bytes takes one Stop condition instead of 64, cutting protocol overhead by >98% and accelerating firmware update or log-save operations in time-sensitive applications.

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

No, the 24FC128-I/P carries the "I" (Industrial) temperature grade (–40°C to +85°C) and is not AEC-Q100 qualified. While it shares the same die as AEC-Q100-certified variants like 24FC128-E/P (Extended temp), the -I/P suffix denotes industrial qualification only. For automotive body electronics or infotainment systems requiring automotive qualification, the 24FC128-E/P or automotive-specific variants must be selected instead.