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Home > Products > Integrated Circuits (ICs) > Memory > Memory

STMicroelectronics M95256-WDW6TP

Name: M95256-WDW6TP
Brand: STMicroelectronics
SKU: M95256-WDW6TP
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: M95256-WDW6TP

Manufacturer:: STMicroelectronics

Category:: Memory

Package:: 8-TSSOP (0.173", 4.40mm Width)

Datasheet:: M95256-WDW6TP.pdf

Description:: IC EEPROM 256KBIT SPI 8TSSOP

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Inventory:8,530

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Product details

Overview

M95256-WDW6TP from STMicroelectronics is a 256-Kbit serial SPI EEPROM organized as 32,768 × 8 bits, operating from 2.5 V to 5.5 V across –40 °C to +85 °C. It supports 20 MHz clock speed, 64-byte page writes completing in ≤5 ms, and offers quarter/half/whole-array write protection via BP1/BP0 bits in its non-volatile status register. Used for firmware parameter storage in industrial controllers where reliable, low-power, byte-addressable nonvolatile memory is required.

For engineers reviewing the M95256-WDW6TP datasheet, M95256-WDW6TP pinout, M95256-WDW6TP application, or M95256-WDW6TP equivalent, key selection considerations include supply voltage range (2.5–5.5 V), SPI mode compatibility (CPOL/CPHA = 0/0 or 1/1), identification page lockability, hold functionality for bus arbitration, and ECOPACK2-compliant TSSOP8 packaging with verified 169-mil width.

Technical Context

This device implements a standard SPI interface with edge-sensitive chip select (S) requiring a falling edge after power-up before instruction acceptance. Serial data input (D) latches on rising clock edges; output (Q) shifts out on falling edges - supporting only CPOL/CPHA = (0,0) and (1,1) modes.

It integrates an internal high-voltage generator and sequencer for EEPROM programming, with ECC-enabled sense amplifiers and a dedicated identification page (64 bytes) that can be permanently locked in read-only mode via LID instruction - a feature distinguishing M95256-WDW6TP from base M95256-W variants.

Key Specifications

Parameter	Value and Actual Design Meaning
Memory size	256 Kbit (32 Kbytes), organized as 32768 × 8 bits - enables full firmware configuration storage without external memory expansion
Interface	SPI bus, CPOL/CPHA = (0,0) or (1,1) - ensures interoperability with most microcontroller SPI peripherals without mode reconfiguration
Write time	≤5 ms per byte or per 64-byte page - allows rapid field updates of calibration data or user settings during system runtime
Supply voltage	2.5 V to 5.5 V - compatible with 3.3 V and 5 V logic domains, eliminating level-shifting in mixed-voltage systems
Data retention	200 years at +25 °C - guarantees long-term integrity of stored device identifiers, security keys, or calibration coefficients
Endurance	4 million write cycles - supports frequent logging or counter updates in telemetry or energy metering applications
Operating temp	–40 °C to +85 °C - validated for deployment in industrial PLCs, motor drives, and outdoor IoT gateways

Pinout & Package

Package: TSSOP8 (169 mil width), ECOPACK2-compliant, surface-mount, 8-lead thin shrink small outline package with exposed pad option not specified.

Pin/Terminal	Circuit Role	Design Meaning
S	Chip select	Active-low enable; falling edge required after power-up to initiate communication - prevents spurious writes during brown-out
C	Serial clock	Input timing reference; data latched on rising edge (D), output shifted on falling edge (Q) - defines maximum 20 MHz throughput
D	Serial data input	Carries instructions, addresses, and write data MSB-first; sampled on rising C edge - supports WREN, WRITE, WRSR, and RDID commands
Q	Serial data output	Drives read data, status register contents, or ID page bytes MSB-first on falling C edge - high-impedance when S is high or HOLD is active
W	Write protect	Hardware control for SRWD bit; when low and SRWD=1, locks BP1/BP0 bits against modification - enables permanent memory partitioning
HOLD	Communication pause	Active-low bus hold; suspends ongoing SPI transfer without resetting internal state - allows MCU to service higher-priority interrupts
V_CC	Supply voltage	2.5–5.5 V power rail; requires local 10–100 nF decoupling - powers internal HV generator and logic core
V_SS	Ground	Reference for all I/O and internal circuitry; must be low-impedance return path - critical for noise immunity during write cycles

Key Features

Feature	Design Value
Identification page	64-byte dedicated area for storing immutable parameters (e.g., MAC address, serial number); lockable via LID instruction to prevent overwrite
Flexible write protection	Software-configurable block protection (BP1/BP0) enabling quarter/half/full array lock - supports hierarchical firmware update schemes
Hold functionality	Pauses SPI transaction mid-stream without deselecting device - preserves command context during MCU interrupt handling
Power-on reset (POR)	Internal POR circuit holds device inactive until V_CC exceeds threshold - eliminates need for external reset supervisor IC
ECOPACK2 packaging	TSSOP8 meets RoHS, halogen-free, and lead-free requirements - satisfies industrial environmental compliance mandates

Applications

Industrial PLC Configuration Storage

Smart Energy Meter Calibration Data

Use Scenario: Storing I/O mapping tables, PID tuning parameters, and alarm thresholds in programmable logic controllers deployed in factory automation.

IC Role / Device Role / Timing Role: Nonvolatile configuration register accessed via SPI during boot and runtime reconfiguration - retains values across power cycles and brown-outs.

Use Value: Enables field-upgradable machine logic without firmware reflashing; 4M write cycles support daily recalibration logs over 10+ years.

Use Scenario: Holding metrology calibration coefficients, tariff tables, and tamper-event timestamps in ANSI C12.22-compliant electricity meters.

IC Role / Device Role / Timing Role: Secure parameter vault with hardware-locked identification page storing cryptographic keys and device serials - accessed only by trusted firmware.

Use Value: Prevents unauthorized parameter modification via W pin + SRWD; 200-year retention ensures lifetime accuracy without battery-backed RAM.

Medical Infusion Pump Safety Settings

Automotive Body Control Module (BCM) Trim Values

Use Scenario: Saving drug library limits, dose safety interlocks, and user-defined profiles in Class II medical infusion pumps certified to IEC 62304.

IC Role / Device Role / Timing Role: Fail-safe configuration store with hold capability - allows MCU to pause EEPROM access during critical motor control sequences.

Use Value: HOLD pin enables deterministic real-time response; -40°C to +85°C rating covers operating range inside sealed pump enclosures.

Use Scenario: Storing seat/mirror position offsets, lighting brightness presets, and door lock behavior in automotive BCMs.

IC Role / Device Role / Timing Role: Low-power SPI EEPROM interfaced to 3.3 V CAN/LIN microcontroller - retains user preferences through ignition cycles.

Use Value: 2.5–5.5 V operation matches automotive 3.3 V domain; TSSOP8 footprint minimizes PCB area vs. SO8N while maintaining reflow compatibility.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
AT25256-SSHL-B	256 Kbit SPI EEPROM, 1.8–5.5 V supply, 20 MHz max clock, but lacks identification page and LID/RDID/WRID instructions	No dedicated lockable ID page; unsuitable for secure device identity storage requiring permanent read-only partition	Select when basic parameter storage suffices and cost sensitivity outweighs security features
M95256-DFMN6TP	Same STMicro family, 1.7–5.5 V supply, includes identification page and LID/RDID/WRID, but in SO8N (150 mil) package instead of TSSOP8	SO8N footprint requires PCB redesign; wider voltage range enables single-BOM use across 1.8 V and 3.3 V systems	Select when board space permits SO8N and ultra-low-voltage operation (<2.5 V) is required

Compared with AT25256-SSHL-B and M95256-DFMN6TP, M95256-WDW6TP uniquely balances 2.5–5.5 V compatibility, TSSOP8 compactness, and hardware-lockable identification page - making it optimal for industrial controllers needing secure, space-constrained, mid-voltage nonvolatile storage.

Availability

M95256-WDW6TP is available at Aetrix Electronics and suitable for industrial PLCs, smart energy meters, medical infusion pumps, and automotive body control modules requiring stable component supply, long-lifecycle assurance, and ECOPACK2-compliant packaging.

Supply support for M95256-WDW6TP 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.

M95256-WDW6TP belongs to ST's serial EEPROM product line, engineered specifically for robust, low-power, SPI-based nonvolatile data storage in harsh environments - emphasizing reliability, security, and drop-in replaceability across voltage grades.

FAQ

What is the function of the HOLD pin on M95256-WDW6TP?

The HOLD pin pauses ongoing SPI communication without deselecting the device or resetting internal state. When driven low while chip select (S) is active, it places Q in high-impedance and ignores D and C signals - allowing the host MCU to service interrupts or reallocate bus resources. Communication resumes upon HOLD returning high, preserving the exact byte position in multi-byte transfers.

Can M95256-WDW6TP be used with a 1.8 V microcontroller SPI interface?

No - M95256-WDW6TP requires a minimum V_CC of 2.5 V and is not guaranteed to operate correctly with 1.8 V logic levels. Its input thresholds (V_IL, V_IH) and output drive strength are specified for 2.5–5.5 V operation. For 1.8 V systems, consider M95256-R or M95256-DF variants, which support down to 1.8 V and 1.7 V respectively.

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 - separate from the main 32 Kbyte array. Once locked with LID, it becomes permanently read-only, protecting critical data like device serial numbers or cryptographic keys from accidental or malicious overwrite, even if BP1/BP0 bits are cleared.

Is M95256-WDW6TP pin-compatible with other M95256 variants in TSSOP8?

Yes - all M95256 variants in TSSOP8 (including M95256-WDW6TP, M95256-RDW6TP, M95256-DFW6TP) share identical pinout, mechanical dimensions, and solder profile. The suffix "W" denotes 2.5–5.5 V operation; "R" and "DF" indicate lower-voltage ranges but retain full functional and physical compatibility in this package.

M95256-WDW6TP Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 8-TSSOP (0.173", 4.40mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Active

Programmable:: Not Verified

Memory Type:: Non-Volatile

Memory Format:: EEPROM

Technology:: EEPROM

Memory Size:: 256Kbit

Memory Organization:: 32K x 8

Memory Interface:: SPI

Clock Frequency:: 20 MHz

Write Cycle Time - Word, Page:: 5ms

Access Time:: -

Voltage - Supply:: 2.5V ~ 5.5V

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 8-TSSOP

M95256-WDW6TP FAQ

1.How can I place an order for M95256-WDW6TP through Aetrix?

Please submit a Request for Quotation (RFQ) for M95256-WDW6TP on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for M95256-WDW6TP reliable?

The price and inventory of M95256-WDW6TP are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M95256-WDW6TP is usually 5 days.

3.What payment methods are accepted for M95256-WDW6TP?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M95256-WDW6TP transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for M95256-WDW6TP?

M95256-WDW6TP orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your M95256-WDW6TP order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for M95256-WDW6TP?

For technical support, including M95256-WDW6TP datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M95256-WDW6TP requirements.

6.How does Aetrix verify that M95256-WDW6TP is sourced from the original manufacturer or authorized distributors?

All M95256-WDW6TP products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that M95256-WDW6TP meets industry standards.

7.What is the process for return or replacement of M95256-WDW6TP?

All M95256-WDW6TP units undergo pre-shipment inspection (PSI). If there is an issue with M95256-WDW6TP, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The M95256-WDW6TP part is unused and in its original packaging.

Return procedure for M95256-WDW6TP:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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