STMicroelectronics M95256-DFMC6TG

Overview

M95256-DFMC6TG from STMicroelectronics is a 256-Kbit serial SPI EEPROM organized as 32,768 × 8 bits, operating from 1.7 V to 5.5 V supply with 20 MHz clock support. It features an additional 64-byte Identification page permanently lockable in read-only mode, 4 million write cycles, and 200-year data retention. Used for secure parameter storage in industrial controllers and IoT edge nodes where low-voltage operation and tamper-resistant configuration are required.

For engineers reviewing the M95256-DFMC6TG datasheet, M95256-DFMC6TG pinout, M95256-DFMC6TG application, or M95256-DFMC6TG equivalent, key selection criteria include 1.7 V minimum VCC compatibility, WLCSP8 package footprint constraints, Identification page lock functionality, and SPI mode (CPOL/CPHA) timing alignment with host MCU peripherals.

Technical Context

This device implements a standard SPI interface with dual-mode clock polarity support (CPOL=0/CPHA=0 and CPOL=1/CPHA=1), latching input on rising C edge and output on falling C edge. It integrates on-chip high-voltage generation for EEPROM programming and includes ECC logic for bit error correction during read operations.

The memory array is partitioned into 512 pages of 64 bytes each, plus one dedicated 64-byte Identification page. Block protection is controlled via non-volatile BP1/BP0 bits in the Status register, enabling quarter/half/full array write lock, while SRWD + W pin enable hardware-level status register write disable.

Key Specifications

Pinout & Package

Package: WLSCP8 (1.289 × 1.376 mm), ECOPACK2-compliant wafer-level chip-scale package with bottom-side solder bumps.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT25SF041-SSHD-B and M95256-WDW6TP, M95256-DFMC6TG uniquely combines ultra-low 1.7 V operation, WLCSP8 miniaturization, and hardware-lockable Identification page-making it optimal for space-constrained, battery-operated, or security-critical embedded systems where parameter integrity is non-negotiable.

Availability

M95256-DFMC6TG is available at Aetrix Electronics and suitable for industrial PLCs, IoT edge sensors, automotive body controllers, and medical diagnostic instruments requiring stable component supply across multi-year production cycles.

Supply support for M95256-DFMC6TG 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 management ICs, MEMS, and nonvolatile memory solutions for industrial, automotive, and consumer markets.

M95256-DFMC6TG belongs to ST's serial EEPROM product line, engineered specifically for reliable, low-voltage, SPI-based configuration and calibration storage in space- and power-constrained embedded systems.

FAQ

What is the function of the HOLD pin on M95256-DFMC6TG?

The HOLD pin pauses ongoing SPI communication without deselecting the device or resetting internal state. When asserted low while Chip Select (S) is low, it places Serial Data Output (Q) in high-impedance and ignores Serial Clock (C) and Serial Data Input (D). This allows the host MCU to temporarily suspend EEPROM access during interrupt servicing or bus arbitration, resuming from the exact bit position upon deassertion.

How does the Identification page differ from the main memory array?

The Identification page is a dedicated 64-byte region accessible only via RDID/WRID/LID instructions-not through standard READ/WRITE commands. Once locked via the LID instruction, it becomes permanently read-only, with no software or hardware method to unlock it. This makes it suitable for storing immutable values like factory calibration data, cryptographic keys, or device serial numbers that must survive firmware updates.

Can M95256-DFMC6TG operate reliably at 1.7 V with full 20 MHz SPI clock speed?

Yes. The 1.7 V minimum supply rating applies across the full commercial temperature range (−40 °C to +85 °C) and supports all specified AC parameters-including 20 MHz clock operation and 5 ms max write time-at that voltage. ST's characterization data confirms tCH/tCL timing margins remain compliant down to 1.7 V, eliminating need for voltage scaling or clock throttling in low-power designs.

What happens if the W pin is left floating during operation?

The W pin must be actively driven high or low; floating violates the absolute maximum ratings and may cause undefined behavior in Block Protect (BP1/BP0) and Status Register Write Disable (SRWD) functionality. If W is unconnected, the internal pull-down is insufficient to guarantee logic levels under noise or leakage conditions. ST recommends connecting W to VSS (for default unprotected mode) or VCC (to disable hardware lock) via a 10 kΩ resistor to ensure deterministic operation.