STMicroelectronics M95640-DFCT6TP/K

Overview

M95640-DFCT6TP/K from STMicroelectronics is a 64-Kbit serial SPI bus EEPROM with 8192 × 8-bit organization, featuring an additional 32-byte lockable identification page for secure parameter storage. It operates from 1.7 V to 5.5 V over –40 °C to +85 °C, supports up to 20 MHz clock frequency, and delivers byte/page write within 3.4 ms (typical), enabling reliable nonvolatile data logging in space-constrained industrial controllers.

For engineers reviewing the M95640-DFCT6TP/K datasheet, M95640-DFCT6TP/K pinout, M95640-DFCT6TP/K application, or M95640-DFCT6TP/K equivalent, key selection criteria include its 1.7 V minimum supply, hardware/software write protection architecture, identification page locking capability, and ECOPACK2-compliant TSSOP8 package compatibility with high-density PCB layouts.

Technical Context

This device implements a standard SPI interface compliant with CPOL=0/CPHA=0 and CPOL=1/CPHA=1 modes, where data is latched on the rising edge of C and output on the falling edge. The internal architecture includes a status register with WIP, WEL, BP1/BP0, and SRWD bits, enabling granular software-based memory protection and hardware-enforced lockout of status register writes when W is low and SRWD is set.

It integrates Schmitt-trigger inputs for noise immunity, on-chip high-voltage generation for EEPROM programming, and ECC-enhanced sense amplifiers. The identification page (address range 0000h–001Fh) is accessible only via dedicated RDID/WRID/LID instructions-unavailable on M95640-W/R variants-and supports permanent read-only lock after programming.

Key Specifications

Pinout & Package

Package: TSSOP8 (169 mil width), ECOPACK2-compliant, RoHS and REACH certified, surface-mount compatible with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT25DF641A-SSHD-B and M95640-RMN6TP/K, the M95640-DFCT6TP/K uniquely combines sub-1.8 V operation, dedicated lockable ID page, and dual-layer (software + hardware) write protection - making it the sole option for secure, ultra-low-power configuration storage in regulated industrial and medical systems.

Availability

M95640-DFCT6TP/K is available at Aetrix Electronics and suitable for industrial PLCs, medical infusion pumps, automotive body control modules, and smart energy meters requiring stable component supply across extended product lifecycles.

Supply support for M95640-DFCT6TP/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 M95640 series belongs to ST's serial EEPROM product line, engineered specifically for robust, low-voltage, secure nonvolatile storage in resource-constrained embedded systems where data integrity and long-term reliability are mission-critical.

FAQ

What is the function of the HOLD pin, and when should it be used?

The HOLD pin pauses ongoing SPI communication without deselecting the device or resetting internal state. It must be asserted while chip select (S) is low and serial clock (C) is low to avoid metastability. Use HOLD during MCU interrupt servicing or multi-master arbitration to prevent transaction corruption - Q goes high-impedance and D/C become don't-care, preserving command context until HOLD is deasserted.

How does the identification page differ from main memory, and how is it locked?

The identification page is a separate 32-byte memory region (addresses 0000h–001Fh) accessible only via RDID, WRID, and LID instructions - unavailable on M95640-W/R variants. Locking is irreversible: executing LID sets a fuse that disables further WRID access and forces RDID to return stored data only. This ensures cryptographic keys or calibration data remain immutable after factory programming.

Can the M95640-DFCT6TP/K operate reliably at 1.7 V during write operations?

Yes - the device guarantees full functionality including byte/page write (≤5 ms), status register reads, and HOLD activation down to 1.7 V at –40 °C to +85 °C. Internal charge pump regulation and Schmitt-trigger inputs maintain timing margins per DS6633 AC specs. No derating or external supervision is needed, unlike competing EEPROMs requiring ≥1.8 V for write cycles.

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

Leaving W floating violates the absolute maximum rating and risks undefined behavior: SRWD bit interpretation becomes unreliable, potentially disabling status register writes unintentionally or allowing unauthorized BP1/BP0 changes. STMicroelectronics specifies W must be actively driven high or low - a 10 kΩ pull-up to VCC is recommended for default unprotected mode, or pull-down for factory-locked configuration.