STMicroelectronics M95256-DFCS6TP/K

Overview

M95256-DFCS6TP/K from STMicroelectronics is a 256-Kbit serial SPI bus EEPROM organized as 32,768 × 8 bits, operating from 1.7 V to 5.5 V over –40 °C to +85 °C. It features a 64-byte page size, 5 ms byte/page write time, hardware- and software-based write protection (quarter/half/whole array), and an additional 64-byte lockable Identification page for secure parameter storage - used in industrial control modules requiring tamper-resistant calibration data.

For engineers reviewing the M95256-DFCS6TP/K datasheet, M95256-DFCS6TP/K pinout, M95256-DFCS6TP/K application, or M95256-DFCS6TP/K equivalent, key selection criteria include supply voltage range (1.7–5.5 V), SPI mode compatibility (CPOL/CPHA = 0/0 or 1/1), Identification page lock capability, WLCSP8 footprint constraints, and 4M write cycle endurance with 200-year data retention.

Technical Context

The device implements a full SPI interface with dedicated HOLD and WRITE PROTECT inputs enabling real-time communication suspension and hierarchical memory locking. Its status register (SRWD, BP1/BP0, WEL, WIP) supports both volatile and non-volatile configuration of protection granularity and write enable state.

It integrates on-chip high-voltage generation for EEPROM programming, ECC logic for data integrity, and a POR circuit ensuring reliable power-up behavior. The Identification page (64 bytes at fixed address) is accessible only via RDID/WRID/LID instructions - exclusive to the -DF variant - and can be permanently locked to read-only mode.

Key Specifications

Pinout & Package

Package: WLSCP8 (1.289 × 1.376 mm), ECOPACK2-compliant wafer-level chip-scale package with bottom-side solder bumps - optimized for space-constrained portable and wearable electronics.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT25SF041-SSHD-B and M95256-WDW6TP, the M95256-DFCS6TP/K uniquely combines ultra-compact WLSCP8 packaging, 1.7 V operation, and a cryptographically isolatable Identification page - making it the only option for space-constrained, low-voltage, safety-certified designs requiring immutable parameter storage.

Availability

M95256-DFCS6TP/K is available at Aetrix Electronics and suitable for industrial PLC I/O modules, medical infusion pump calibration, and smart energy meter firmware storage requiring stable component supply, long-lifecycle assurance, and ECOPACK2-compliant packaging.

Supply support for M95256-DFCS6TP/K 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.

The M95256 series belongs to ST's serial EEPROM product line, engineered specifically for robust, low-power, secure non-volatile storage in space- and voltage-constrained embedded systems - emphasizing write endurance, data retention, and hardware-enforced protection.

FAQ

What is the function of the Identification page in M95256-DFCS6TP/K?

The Identification page is a dedicated 64-byte memory region accessible only via RDID, WRID, and LID instructions. It stores sensitive data such as cryptographic keys or calibration parameters and can be permanently locked to read-only mode using the LID command - a feature exclusive to the -DF variant and not present in -W or -R versions.

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

When HOLD is driven low while Chip Select (S) is low and Serial Clock (C) is low, the device suspends communication immediately: Q goes high-impedance, and D/C become don't-care. The internal state (address counter, instruction decode) is preserved - resuming on HOLD high without reinitialization. This enables deterministic pause/resume in real-time systems with tight timing budgets.

Can M95256-DFCS6TP/K operate reliably at 1.7 V supply?

Yes - the -DF suffix denotes guaranteed operation from 1.7 V to 5.5 V across –40 °C to +85 °C. At 1.7 V, write time remains ≤5 ms, and SPI clock supports up to 10 MHz (derated from 20 MHz at ≥2.5 V). All DC/AC parameters in DS4712 Rev 22 are fully characterized down to 1.7 V.

What happens if the Write Protect (W) pin is left floating?

The W pin must be actively driven high or low; floating violates the absolute maximum ratings and may cause unpredictable status register behavior. If W is high, hardware protection is disabled. If W is low and SRWD = 1, the Status register becomes permanently read-only - preventing further changes to BP1/BP0 and SRWD bits until next power cycle.