Microchip Technology 24FC128-I/SN

Overview

24FC128-I/SN 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-protection via WP pin, 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/SN datasheet, 24FC128-I/SN pinout, 24FC128-I/SN application, or 24FC128-I/SN equivalent, key selection criteria include its 1 MHz I²C speed advantage over 24AA128/24LC128 variants, SOIC-8 (SN) package compatibility, 1 µA standby current, and page-write timing of ≤5 ms - critical for low-power, high-throughput nonvolatile memory interfacing in resource-constrained designs.

Technical Context

The 24FC128-I/SN implements a two-wire I²C slave interface with fixed 7-bit address prefix '1010' and user-configurable A0–A2 chip-select bits enabling up to eight devices on one bus. Its internal architecture includes a 64-byte page latch, EEPROM array with automatic erase-before-write, and HV generator for programming.

It supports byte and page write modes, random/sequential reads across full 128K boundary, and acknowledge polling for write-cycle completion detection. The WP pin provides hardware-level write protection for the entire memory array (0000h–3FFFh), sampled only at the Stop condition of each write command.

Key Specifications

Pinout & Package

24FC128-I/SN is supplied in an 8-lead plastic small outline (SOIC-N) package, designated SN per Microchip's packaging standard (drawing C04-057-SN Rev E), with 3.90 mm body width, gull-wing leads, and JEDEC MS-012AC compliant footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA128-I/SN, the 24FC128-I/SN delivers 2.5× faster write throughput and identical low-voltage operation, while AT24C128-10PU-2.7 offers comparable speed but sacrifices 1.7V compatibility and SOIC-8 mechanical fit - making 24FC128-I/SN optimal for new 1.8V–3.3V designs demanding both performance and footprint continuity.

Availability

24FC128-I/SN is available at Aetrix Electronics and suitable for industrial sensor nodes, automotive body control modules, and medical device calibration requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant sourcing.

Supply support for 24FC128-I/SN 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 operations.

The 24FC128-I/SN belongs to Microchip's 24XX128 family of serial EEPROMs, engineered for ultra-low-power, high-reliability nonvolatile storage in space-constrained embedded systems across industrial, automotive, and medical markets.

FAQ

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

The 24FC128-I/SN supports up to 1 MHz I²C clock frequency when V_CC is 2.5V or higher. At V_CC between 1.7V and 2.5V, the maximum clock rate drops to 400 kHz. This dual-speed capability allows seamless integration into both legacy 400 kHz systems and modern high-throughput designs - a key differentiator from the 24AA128-I/SN and 24LC128-I/SN variants. The 24FC128-I/SN datasheet (DS20001191T) confirms this behavior in Table 1-2, AC Characteristics.

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

Yes, the 24FC128-I/SN 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; and for 100 kHz, 10 kΩ suffices. These values ensure rise times meet AC specs (TR ≤ 300 ns at 1 MHz) while minimizing bus loading. The 24FC128-I/SN datasheet specifies this in Section 2.2 (SDA) and Section 2.3 (SCL).

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

The WP pin on the 24FC128-I/SN provides hardware-level write protection: when tied to V_CC, all write operations (byte and page) are inhibited, though read operations remain fully functional. The pin state is sampled only at the Stop condition of each write command - toggling WP mid-cycle has no effect. This enables safe field updates where configuration data must persist across firmware upgrades. The 24FC128-I/SN datasheet details this in Section 2.4 and Figure 1-1.

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

The 24FC128-I/SN features a 64-byte page write buffer, meaning up to 64 bytes can be loaded into the internal latch and written to memory in a single self-timed cycle (≤5 ms). This reduces I²C transaction overhead dramatically: writing 64 bytes requires only one Start–Stop sequence instead of 64 separate byte writes. For applications like logging sensor snapshots or updating UI strings, this cuts bus occupancy by >98%. The 24FC128-I/SN datasheet specifies this in the Features list and Section 6.2.

Is the 24FC128-I/SN compatible with the 24AA128-I/SN in terms of pinout and software interface?

Yes, the 24FC128-I/SN is pinout- and protocol-compatible with the 24AA128-I/SN in the same SOIC-8 (SN) package: identical A0–A2, V_SS, SDA, SCL, WP, and V_CC pin assignments and identical I²C addressing, read/write sequences, and ACK polling behavior. Software drivers require no modification - only timing margins may need adjustment to leverage the 24FC128-I/SN's 1 MHz capability. This compatibility is confirmed across the shared DS20001191T datasheet for all 24XX128 variants.