STMicroelectronics M24256-DFDW6TP

Overview

M24256-DFDW6TP from STMicroelectronics is a 256-Kbit I²C-compatible serial EEPROM organized as 32 K × 8 bits, operating from 1.7 V to 5.5 V with 1 MHz clock support. It features a 64-byte page size, an additional write-lockable identification page, and enhanced ESD/latch-up protection. Used in industrial control modules for parameter storage and firmware revision tracking.

For engineers reviewing the M24256-DFDW6TP datasheet, M24256-DFDW6TP pinout, M24256-DFDW6TP application, or M24256-DFDW6TP equivalent, key selection criteria include supply voltage range (1.7–5.5 V), I²C bus speed compatibility (100 kHz/400 kHz/1 MHz), identification page lockability, and TSSOP8 ECOPACK2 packaging for space-constrained PCB layouts.

Technical Context

The device implements a standard I²C slave protocol with 7-bit device addressing and configurable chip enable inputs (E2–E0) that set the three LSBs of the device address. It supports byte and page write modes (up to 64 bytes per page), with internal ECC logic correcting single-bit errors across groups of four consecutive bytes.

Write control (WC) enables hardware-level memory protection: driving WC high disables all writes to the main array and identification page. The identification page-exclusive to M24256-D variants-is accessible via a dedicated device select code (1011b) and supports permanent lock via a specific address/data pattern.

Key Specifications

Pinout & Package

TSSOP8 (DW) package, 169 mil width, RoHS-compliant and halogen-free (ECOPACK2). Pin 1 marked by notch or dot; leads are gull-wing, surface-mount compatible.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT24C256-SSHL-T and BR24G256FJ-3GE2, M24256-DFDW6TP uniquely delivers a dedicated, permanently lockable 64-byte identification page-critical for secure device identity management in regulated markets.

Availability

M24256-DFDW6TP is available at Aetrix Electronics and suitable for industrial sensor calibration, smart meter firmware storage, and automotive body control modules requiring stable component supply across multi-year production cycles.

Supply support for M24256-DFDW6TP 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power ICs, sensors, and memory solutions for industrial, automotive, and consumer markets.

M24256-DFDW6TP belongs to ST's M24 serial EEPROM product line, engineered specifically for robust, low-power, I²C-based nonvolatile storage in harsh environments with stringent data integrity and security requirements.

FAQ

What is the function of the WC pin on M24256-DFDW6TP?

The WC (Write Control) pin provides hardware-level write protection: when driven high, it disables all write operations to both the main memory array and the identification page. When low or left floating, writes are enabled. This prevents accidental overwrites during power-up transients or firmware faults, and is independent of I²C command execution.

How does the identification page differ from standard memory pages?

The identification page is a dedicated 64-byte section accessible only via a unique I²C device address prefix (1011b). Unlike standard pages, it supports a permanent lock command: once locked, no further writes are possible-even with WC low-and the lock cannot be reversed. It is intended for immutable data such as device serial numbers or cryptographic keys.

Can M24256-DFDW6TP operate reliably at 1.7 V and 1 MHz?

Yes. The M24256-DF variant is explicitly rated for full 1 MHz I²C operation across the entire 1.7 V to 5.5 V supply range. This is confirmed in DS1766 Rev 35 AC characteristics (Table 10), where t_BUF, t_HD;STA, and t_LOW meet 1 MHz timing requirements at V_CC = 1.7 V and T_A = +85 °C.

What is the purpose of ECC in this EEPROM?

The built-in ECC corrects single-bit errors in real time across every group of four consecutive bytes. It operates transparently during reads-no firmware intervention needed-and improves long-term data reliability without increasing access latency. During writes, ECC logic automatically updates all four bytes in the group, distributing endurance wear across the quartet.