STMicroelectronics M95256-DWDW4TP/K

Overview

M95256-DWDW4TP/K from STMicroelectronics is an AEC-Q100 Grade 0 qualified 256-Kbit serial SPI EEPROM in TSSOP8 package, supporting 20 MHz clock at V_CC ≥ 4.5 V, 64-byte page write within 4 ms, and operation up to 145 °C with 2.5–5.5 V supply. It integrates an identification page (64 bytes), block-level write protection (1/4, 1/2, or full memory), and embedded ECC for enhanced data integrity in automotive powertrain and ADAS control modules.

For engineers reviewing the M95256-DWDW4TP/K datasheet, M95256-DWDW4TP/K pinout, M95256-DWDW4TP/K application, or M95256-DWDW4TP/K equivalent, this page delivers verified timing parameters, SPI mode compatibility (CPOL=0/1, CPHA=0/1), hold functionality, status register behavior, and real-world endurance metrics (4M cycles at 25 °C, 400k at 145 °C) critical for high-reliability automotive firmware storage.

Technical Context

This device implements a true EEPROM array organized as 32,768 × 8 bits (512 pages × 64 bytes), with Schmitt-trigger inputs for noise immunity and dual-mode SPI support (CPOL=0, CPHA=0 and CPOL=1, CPHA=1). Data is latched on the rising edge of Serial Clock (C), and output shifts on its falling edge - matching standard microcontroller SPI peripherals without custom timing logic.

It features a dedicated Status Register with WIP (Write In Progress), WEL (Write Enable Latch), BP1/BP0 (block protection), and SRWD (Status Register Write Disable) bits - enabling hardware- and software-controlled write lock granularity. The HOLD pin allows pausing ongoing transfers without deselecting the device, preserving internal state across transient bus arbitration.

Key Specifications

Pinout & Package

TSSOP8 (DW) package: 3 mm × 4.4 mm body, 0.65 mm pitch, RoHS-compliant and halogen-free (ECOPACK2®).

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT25DF041A-SSH-T, M95256-DWDW4TP/K trades density for automotive-grade reliability and embedded ECC; versus M95256-DFDW4TP/K, it delivers superior thermal performance in compact form factor - making it optimal for space-constrained, high-temp ECU placements.

Availability

M95256-DWDW4TP/K is available at Aetrix Electronics and suitable for automotive powertrain control, ADAS sensor calibration, and EV battery management systems requiring stable component supply across extended product lifecycles.

Supply support for M95256-DWDW4TP/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 specializing in automotive, industrial, and power management ICs, with over 30 years of EEPROM innovation and AEC-Q100 qualification expertise.

M95256-DWDW4TP/K belongs to ST's automotive-qualified serial EEPROM product line, engineered specifically for mission-critical data storage in harsh-temperature automotive subsystems where reliability and longevity are non-negotiable.

FAQ

What SPI modes does M95256-DWDW4TP/K support?

It supports two SPI modes: CPOL=0, CPHA=0 and CPOL=1, CPHA=1. In both, data is latched on the rising edge of Serial Clock (C) and output shifts on the falling edge. The difference lies only in idle clock polarity - ensuring compatibility with most automotive-grade microcontrollers without requiring custom driver modifications.

How does the HOLD pin function during active communication?

HOLD pauses ongoing SPI transfers when driven low while Serial Clock (C) is low; Q goes high-impedance, and D/C signals are ignored. Communication resumes when HOLD returns high and C is low. This preserves internal address and instruction state - critical for interrupt-driven firmware that must temporarily suspend EEPROM access without aborting writes.

Can the Identification Page be written after initial programming?

Yes - the 64-byte Identification Page can be written using the WRID instruction, provided the Write Enable Latch (WEL) is set. Once locked via the LID command, it becomes permanently read-only. This enables secure provisioning of cryptographic keys or calibration data in manufacturing, then locking before vehicle deployment.

What is the impact of V_CC on maximum clock frequency?

Maximum SPI clock scales with supply voltage: 20 MHz at V_CC ≥ 4.5 V, 10 MHz at V_CC ≥ 2.5 V, and 5 MHz at V_CC ≥ 1.7 V. This ensures robust timing margins across automotive battery voltage transients (e.g., cold crank at 6 V or load dump at 16 V), with automatic frequency adaptation in host firmware.