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STMicroelectronics M95256-WMN6P
- Part No.:
- M95256-WMN6P
- Manufacturer:
- STMicroelectronics
- Category:
- Memory
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
M95256-WMN6P.pdf
- Description:
- IC EEPROM 256KBIT SPI 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:8,685
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Product details
Overview
M95256-WMN6P from STMicroelectronics is a 256-Kbit serial SPI bus EEPROM organized as 32,768 × 8 bits, operating from 2.5 V to 5.5 V supply at up to 20 MHz clock speed, with 64-byte page write capability, hardware/software write protection (quarter/half/whole array), and >4 million write cycles. It serves as nonvolatile configuration storage in industrial controllers, automotive body modules, and smart metering systems requiring robust data retention.
For engineers reviewing the M95256-WMN6P datasheet, M95256-WMN6P pinout, M95256-WMN6P application, or M95256-WMN6P equivalent, key selection criteria include its 20 MHz SPI interface timing, dual-level write protection (BP bits + W pin), Identification page lockability, 5 ms max page write time, and ECOPACK2-compliant SO8N/TSSOP8/UFDFPN8/WLCSP8 packaging options.
Technical Context
This EEPROM implements a standard SPI interface with CPOL=0/CPHA=0 or CPOL=1/CPHA=1 mode support, using dedicated D (input), Q (output), C (clock), S (chip select), W (write protect), and HOLD (communication pause) signals. Internal logic includes a status register with WIP, WEL, BP1/BP0, and SRWD bits for real-time operation control and memory protection state tracking.
The device integrates an on-chip high-voltage generator and sequencer for byte/page programming, ECC-enabled sense amplifiers, and a page latch architecture enabling atomic 64-byte writes. Its Identification page (64 bytes) supports permanent read-only locking via LID instruction - a feature exclusive to M95256-Dx variants including this part's -W suffix variant with extended voltage range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Memory size | 256 Kbit (32 Kbytes), organized as 32,768 × 8 bits - sufficient for firmware parameter tables, calibration data, or device identity storage |
| SPI clock frequency | Up to 20 MHz - enables fast configuration loading in real-time systems without CPU overhead |
| Write time | ≤5 ms per byte or per 64-byte page - ensures deterministic update latency for critical settings |
| 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 designs |
| Data retention | 200+ years - guarantees long-term reliability in unattended infrastructure applications |
| Endurance | 4 million write cycles - supports frequent field-updatable parameters in telemetry or diagnostics subsystems |
| Operating temperature | −40 °C to +85 °C - validated for industrial and under-hood automotive environments |
Pinout & Package
Package: SO8N (150 mil width), RoHS-compliant ECOPACK2.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 (S) | Chip select | Active-low enable signal; falling edge required after power-up before first instruction; deselect resets internal state |
| 2 (W) | Write protect | Hardware lock input; when low + SRWD=1, prevents modification of BP1/BP0/SRWD bits in status register |
| 3 (VSS) | Ground | Reference for all I/O and internal circuitry; must be decoupled near pin with 10–100 nF capacitor |
| 4 (C) | Serial clock | Timing reference for SPI; data latched on rising edge (D), output valid on falling edge (Q); supports CPOL/CPHA 00 or 11 |
| 5 (Q) | Serial data output | Tri-state open-drain output; driven only when S is low and instruction requires readback (e.g., RDSR, READ) |
| 6 (HOLD) | Hold control | Pauses ongoing SPI transaction without deselecting device; Q goes high-impedance while D/C ignored |
| 7 (VCC) | Supply voltage | 2.5–5.5 V power rail; internal POR circuit ensures safe initialization below VCC(min) |
| 8 (D) | Serial data input | Instruction/address/data input; MSB-first; sampled on rising edge of C; requires stable VIH/VIL levels per datasheet |
Key Features
| Feature | Design Value |
|---|---|
| Identification page | 64-byte dedicated area with LID instruction for permanent read-only locking - ideal for storing cryptographic keys or calibration constants |
| Flexible write protection | Configurable via BP1/BP0 bits (software) and W pin (hardware) - enables layered security for boot code vs. runtime data |
| High-speed SPI interface | 20 MHz max clock with guaranteed tSHCH timing - reduces configuration time by >3× vs. legacy 5 MHz EEPROMs |
| ECOPACK2 packaging | SO8N, TSSOP8, UFDFPN8, and WLCSP8 options - supports cost-sensitive through-hole, space-constrained SMT, and ultra-dense mobile designs |
| Robust power sequencing | Built-in POR and edge-sensitive S input - eliminates spurious writes during brown-out or reset conditions |
Applications
| Industrial PLC I/O Modules | Automotive Body Control Units |
|---|---|
Use Scenario: Storing calibrated sensor offsets and actuator dead-band values across power cycles in programmable logic controller expansion modules. IC Role / Device Role / Timing Role: Nonvolatile configuration storage with deterministic 5 ms page write and 200-year retention - ensuring field-deployed units maintain accuracy over 15+ year service life. Use Value: Eliminates need for external battery-backed RAM; reduces BOM count and improves MTBF by removing mechanical battery holders and associated leakage paths. | Use Scenario: Holding door lock sequence logic, mirror position presets, and lighting profile configurations in vehicle body domain controllers. IC Role / Device Role / Timing Role: SPI-accessible EEPROM interfacing directly with 3.3 V microcontroller GPIOs; operates reliably across −40 °C to +85 °C ambient with no derating. Use Value: Enables OEM-specific personalization without firmware reflash; supports over-the-air updates to user preferences via secure bootloader using Identification page locking. |
| Smart Electricity Meters | Medical Infusion Pumps |
Use Scenario: Recording tariff schedules, billing cycle counters, and tamper-event logs in ANSI C12.22-compliant utility meters. IC Role / Device Role / Timing Role: High-endurance (4M cycle) data logger with hardware write protect (W pin) - prevents accidental corruption during grid transients or ESD events. Use Value: Meets IEC 62056-21 data integrity requirements; eliminates need for redundant EEPROMs or complex CRC validation schemes. | Use Scenario: Storing drug library parameters, dose limits, and clinician-configured alarm thresholds in FDA-cleared infusion delivery systems. IC Role / Device Role / Timing Role: Safety-critical configuration store with locked Identification page - stores immutable calibration coefficients verified during factory test and sealed permanently. Use Value: Supports ISO 13485 traceability; satisfies IEC 62304 software safety classification by isolating certified parameters from field-modifiable settings. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar serial EEPROM applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| AT25SF041-SSHN-B | 4 Mbit density, quad SPI interface, 104 MHz max clock, 1.7–2.0 V supply only | Higher bandwidth but narrower voltage range; lacks Identification page and hardware W pin protection | Select when system requires faster bulk reads and has stable 1.8 V rail; avoid where 2.5–5.5 V compatibility or secure parameter locking is mandatory |
| M95256-DRMN6TP | Same 256 Kbit density and pinout, but 1.8–5.5 V supply and TSSOP8 package (vs. SO8N) | Identical functionality with lower minimum VCC; TSSOP8 offers better thermal dissipation than SO8N in high-density layouts | Select for 1.8 V–compatible designs or when board layout favors TSSOP8 footprint; verify PCB land pattern compatibility before migration |
Compared with AT25SF041-SSHN-B and M95256-DRMN6TP, M95256-WMN6P uniquely combines wide 2.5–5.5 V operation, hardware-assisted write protection via W pin, and permanent Identification page locking - making it optimal for industrial and automotive applications demanding voltage flexibility and secure parameter management.
Availability
M95256-WMN6P is available at Aetrix Electronics and suitable for industrial PLC I/O modules, automotive body control units, and smart electricity meters requiring stable component supply, long-lifecycle support, and ECOPACK2-compliant packaging.
Supply support for M95256-WMN6P 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, delivering intelligent power, sensing, and connectivity solutions for industrial, automotive, and consumer markets.
M95256-WMN6P belongs to ST's serial EEPROM product line, engineered specifically for reliable, low-power, SPI-based nonvolatile storage in harsh environments - emphasizing data integrity, long-term retention, and seamless integration with microcontroller peripherals.
FAQ
What is the function of the HOLD pin on M95256-WMN6P?
The HOLD pin pauses ongoing SPI communication without deselecting the device or resetting internal state. When asserted low while chip select (S) is active, Q enters high-impedance and D/C are ignored, allowing the host MCU to service higher-priority interrupts. Communication resumes immediately upon HOLD deassertion, preserving bit/byte alignment - critical for deterministic real-time systems.
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 instructions (not standard READ/WRITE). It supports permanent locking via LID instruction, making contents read-only for life. Unlike main array pages, it cannot be erased independently and is intended for immutable data like calibration coefficients, device serial numbers, or cryptographic keys - enforced by separate address decoding and lock logic.
Can M95256-WMN6P operate at 1.8 V?
No. M95256-WMN6P is rated for 2.5 V to 5.5 V supply only. For 1.8 V operation, use M95256-R or M95256-DF variants, which share identical pinout and instruction set but feature extended low-voltage capability. Attempting to power M95256-WMN6P below 2.5 V may cause unpredictable behavior, failed writes, or incomplete status register reads due to internal voltage monitor thresholds.
What happens if Chip Select (S) is driven high mid-transaction?
Driving S high mid-transaction aborts the current instruction and places the device in Standby mode. If a WRITE or WRSR command was partially received, the internal write cycle will not initiate - no data is altered. However, if S rises precisely after the eighth bit of a valid WRITE instruction, the self-timed write cycle begins immediately. This edge-triggered behavior ensures deterministic start timing and prevents partial writes from corrupting memory.
M95256-WMN6P Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- 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-SOIC
M95256-WMN6P FAQ
1.How can I place an order for M95256-WMN6P through Aetrix?
Please submit a Request for Quotation (RFQ) for M95256-WMN6P 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-WMN6P reliable?
The price and inventory of M95256-WMN6P are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for M95256-WMN6P is usually 5 days.
3.What payment methods are accepted for M95256-WMN6P?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for M95256-WMN6P transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for M95256-WMN6P?
M95256-WMN6P orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your M95256-WMN6P 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-WMN6P?
For technical support, including M95256-WMN6P datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your M95256-WMN6P requirements.
6.How does Aetrix verify that M95256-WMN6P is sourced from the original manufacturer or authorized distributors?
All M95256-WMN6P 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-WMN6P meets industry standards.
7.What is the process for return or replacement of M95256-WMN6P?
All M95256-WMN6P units undergo pre-shipment inspection (PSI). If there is an issue with M95256-WMN6P, 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-WMN6P part is unused and in its original packaging.
Return procedure for M95256-WMN6P:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
M95256-WMN6P Tags
-
M24C02-WMN6TP
STMicroelectronics
-
AT24C02C-XHM-T
Microchip Technology
-
AT21CS01-STUM10-T
Microchip Technology
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AT24C02C-SSHM-T
Microchip Technology
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24LC01BT-I/OT
Microchip Technology
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M24C02-FMC6TG
STMicroelectronics
-
AT24CS02-SSHM-T
Microchip Technology
-
93LC46BT-I/OT
Microchip Technology
-
AT24C04C-SSHM-T
Microchip Technology
-
24LC01BT-I/SN
Microchip Technology
-
24AA02UIDT-I/OT
Microchip Technology
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AT24C08C-STUM-T
Microchip Technology
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