STMicroelectronics M95040-DFDW6TP

Overview

M95040-DFDW6TP from STMicroelectronics is a 4-Kbit (512-byte) serial SPI bus EEPROM with 1.7 V to 5.5 V single-supply operation, 20 MHz max clock frequency, and an additional 16-byte identification page that supports permanent read-only lock. It features ECC x1 bit correction, >4 million write cycles, and 200-year data retention - deployed in industrial control modules for parameter storage and firmware revision tracking.

For engineers reviewing the M95040-DFDW6TP datasheet, M95040-DFDW6TP pinout, M95040-DFDW6TP application, or M95040-DFDW6TP equivalent, key selection criteria include supply voltage range (1.7–5.5 V), identification page programmability, quarter/half/whole-array write protection, SPI mode compatibility (CPOL/CPHA = 0/0 or 1/1), and ECOPACK2-compliant DFN8 (2 × 3 mm) packaging.

Technical Context

This EEPROM implements a synchronous SPI interface with dual-phase clocking: data input (D) latched on rising C edge, data output (Q) valid on falling C edge. It supports two standard SPI modes (CPOL=0/CPHA=0 and CPOL=1/CPHA=1) and includes a dedicated HOLD pin to pause transactions without chip deselection.

The device integrates an internal high-voltage generator and sequencer for write operations, a status register with WIP/WEL/BP1/BP0 bits, and transparent ECC x1 logic per byte. Its identification page (16 bytes) is accessible only via RDID/WRID/LID instructions and can be permanently locked to prevent overwrite - a feature absent in M95040-W and M95040-R variants.

Key Specifications

Pinout & Package

Supplied in RoHS- and halogen-free ECOPACK2-compliant DFN8 package (2 mm × 3 mm, 0.5 mm pitch), with wettable flank side walls for automated optical inspection (AOI) and enhanced solder joint reliability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with M95040-WDW6TP and AT25DF041A-MAU-T, the M95040-DFDW6TP uniquely combines ultra-low-voltage operation (1.7 V), dedicated lockable ID page, and HOLD functionality - making it optimal for safety- or regulation-driven embedded systems where parameter immutability and robust interrupt handling are essential.

Availability

M95040-DFDW6TP is available at Aetrix Electronics and suitable for industrial sensor nodes, smart energy meters, automotive body control modules, and medical infusion pumps requiring stable component supply across extended product lifecycles.

Supply support for M95040-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, specializing in microcontrollers, power management, sensors, and nonvolatile memory solutions for industrial, automotive, and consumer markets.

The M950x0 family delivers SPI EEPROMs optimized for reliability-critical embedded systems - emphasizing extended voltage range, high endurance, ECC protection, and secure parameter storage through features like the identification page lock.

FAQ

What is the purpose of the identification page in M95040-DFDW6TP?

The identification page is a dedicated 16-byte memory region accessible only via RDID, WRID, and LID instructions. Once locked using LID, it becomes permanently read-only - ideal for storing immutable device identifiers, cryptographic keys, or regulatory metadata that must survive field updates and prevent tampering.

How does the HOLD pin function during an active SPI transaction?

The HOLD pin pauses communication without resetting the internal state machine: when driven low while C is low, Q goes high-impedance and D/C are ignored, preserving the current address pointer and instruction context. Resuming requires driving HOLD high while C remains low - enabling deterministic interruption during MCU interrupt service routines.

Can M95040-DFDW6TP operate reliably at 1.7 V while maintaining 20 MHz SPI speed?

Yes - the 1.7 V minimum supply is fully validated for 20 MHz operation across the −40 °C to +85 °C range per DS1639 Rev 14. Internal charge pump and voltage regulator ensure stable core biasing, and timing parameters (tSHSL, tSLCH, tCHSH) remain within spec at 1.7 V, enabling direct interface with ultra-low-power MCUs.

What happens to the status register during an ongoing write cycle?

During a write cycle, the WIP bit remains '1' and is readable via RDSR; the WEL bit resets to '0' upon completion. BP1/BP0 bits retain their pre-write values until WRSR completes. The status register is always readable - even mid-write - allowing host firmware to poll WIP without blocking other operations.