Microchip Technology 24FC512-I/ST

Overview

24FC512-I/ST from Microchip Technology Inc. is a 512 Kbit I²C-compatible serial EEPROM organized as 64K × 8-bit, operating from 1.7V to 5.5V with industrial temperature range (–40°C to +85°C), 1 MHz max clock frequency at V_CC ≥ 2.5V, and hardware write-protection via the WP pin. It is used in embedded systems for nonvolatile parameter storage, calibration data retention, and firmware configuration backup.

For engineers reviewing the 24FC512-I/ST datasheet, 24FC512-I/ST pinout, 24FC512-I/ST application, or 24FC512-I/ST equivalent, key selection criteria include its 1 MHz I²C speed capability, 128-byte page write buffer, 1 µA standby current, Schmitt-trigger inputs for noise immunity, and SOIC-8 package compatibility with legacy board layouts.

Technical Context

The 24FC512-I/ST implements a two-wire I²C interface with open-drain SDA/SCL pins requiring external pull-ups, supports up to eight devices on one bus via A0–A2 address inputs, and uses internal address pointer logic for sequential reads across the full 512 Kbit memory space. Its architecture includes on-chip page latches, HV generator for EEPROM programming, and memory control logic managing self-timed erase/write cycles.

It features Schmitt-trigger inputs on SDA and SCL (V_HYS = 0.05 V_CC), slope-controlled outputs to suppress ground bounce, and write protection activated when WP = V_CC. The device samples WP at the Stop bit of each write command and ignores subsequent WP transitions during the write cycle.

Key Specifications

Pinout & Package

24FC512-I/ST is supplied in an 8-lead SOIC (Small Outline Integrated Circuit) package, designated by suffix "ST", with standard 150 mil body width and gull-wing leads compatible with automated PCB assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 24AA512-I/ST and AT24C512BN-SH-B, the 24FC512-I/ST uniquely combines 1 MHz I²C performance, full 1.7–5.5V operation, and AEC-Q100 qualification-making it optimal for automotive and high-reliability industrial designs demanding both speed and wide-voltage robustness.

Availability

24FC512-I/ST 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, long-term lifecycle support, and RoHS-compliant sourcing.

Supply support for 24FC512-I/ST 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 microcontroller, mixed-signal, analog, and Flash-IP solutions, serving automotive, industrial, consumer, and communications markets with vertically integrated silicon and development tools.

The 24FC512 belongs to Microchip's 24XX512 family of I²C serial EEPROMs, designed specifically for reliable, low-power nonvolatile data storage in space- and power-constrained embedded systems requiring fast write capability and robust noise immunity.

FAQ

What is the maximum I²C clock frequency supported by the 24FC512-I/ST?

The 24FC512-I/ST supports up to 1 MHz I²C clock frequency when V_CC is 2.5V or higher. At V_CC < 2.5V, the maximum clock frequency drops to 400 kHz. This dual-speed capability allows designers to maintain high throughput in 3.3V/5V systems while retaining compatibility with low-voltage 1.8V microcontrollers operating in reduced-speed mode. The 24FC512-I/ST datasheet explicitly confirms this behavior in Table 1-2.

Does the 24FC512-I/ST require external pull-up resistors on SDA and SCL lines?

Yes, the 24FC512-I/ST requires external pull-up resistors on both SDA and SCL lines because these pins are open-drain. 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 is sufficient. These values ensure proper rise times (≤300 ns for SDA/SCL at 1 MHz) and noise margin while avoiding excessive current draw. The 24FC512-I/ST datasheet specifies this requirement in Section 2.2 and Table 1-2.

How does hardware write-protection work on the 24FC512-I/ST?

Hardware write-protection on the 24FC512-I/ST is controlled by the WP pin: when WP is tied to V_CC, all write operations (byte and page) are inhibited, though read operations remain fully functional. The device samples WP at the Stop bit of each write command, and toggling WP after that point has no effect. This feature prevents accidental overwrites during power-up/down or firmware glitches. The 24FC512-I/ST datasheet details this behavior in Sections 2.4 and 6.3.

What is the page write buffer size of the 24FC512-I/ST, and how does it affect write efficiency?

The 24FC512-I/ST features a 128-byte page write buffer, allowing up to 128 bytes to be loaded into the buffer before initiating the internal write cycle. This eliminates the need for 128 separate I²C write transactions, significantly reducing bus overhead and total programming time. Because the buffer operates within a single physical page (aligned to 128-byte boundaries), software must ensure writes do not cross page boundaries-a constraint documented in Section 6.2 of the 24FC512-I/ST datasheet.

Is the 24FC512-I/ST qualified for automotive applications?

Yes, the 24FC512-I/ST is AEC-Q100 qualified for automotive applications, meeting Grade 2 temperature requirements (–40°C to +105°C ambient). Although the "I" suffix denotes Industrial grade (–40°C to +85°C), the underlying 24FC512 die is AEC-Q100 certified, and the SOIC-8 package variant 24FC512-I/ST is approved for use in automotive body electronics, infotainment, and ADAS subsystems where extended temperature operation is not required. This qualification is stated in the Features section of the 24FC512-I/ST datasheet.