STMicroelectronics M93C66-WMN6P

Overview

M93C66-WMN6P from STMicroelectronics is a 4-Kbit serial EEPROM with MICROWIRE™ interface, configurable as 512 × 8-bit or 256 × 16-bit memory, operating from 2.5 V to 5.5 V supply at up to 2 MHz clock frequency, and rated for -40 °C to +85 °C industrial temperature range. It delivers byte/word/page write within 5 ms, supports READY/BUSY signaling, and is used in microcontroller-based system configuration storage where nonvolatile parameter retention is required.

For engineers reviewing the M93C66-WMN6P datasheet, M93C66-WMN6P pinout, M93C66-WMN6P application, or M93C66-WMN6P equivalent, key selection considerations include its dual x8/x16 organization select (ORG pin), 4 million write cycles at 25°C, 200-year data retention, SO8N package compatibility, and MICROWIRE™ bus timing compliance per DS1077 Rev 20.

Technical Context

The M93C66-WMN6P implements a static CMOS serial EEPROM architecture with on-chip clock pulse counter for noise immunity and hardware-level write protection via WEN/WDS instructions. Its ORG pin selects between 512-byte or 256-word memory mapping, and all instructions-including READ, WRITE, ERASE, WRAL-are synchronized to the rising edge of the Serial Clock (C) with start-bit detection.

During programming, it autonomously executes erase-before-write, reports status via Q pin (READY=high, BUSY=low), and enforces strict clock cycle counting to abort misaligned commands-ensuring deterministic behavior in noisy embedded environments without host-side retry logic.

Key Specifications

Pinout & Package

Package: SO8N (150 mil width), 8-pin small outline integrated circuit, ECOPACK2-compliant, surface-mount.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AT25040B-SSHL-T and BR24G04FJ-WE2, the M93C66-WMN6P uniquely supports MICROWIRE™-native dual-organization memory mapping and real-time READY/BUSY status reporting-enabling tighter timing control and flexible data structure alignment in legacy or resource-limited microcontroller platforms.

Availability

M93C66-WMN6P is available at Aetrix Electronics and suitable for industrial sensor calibration storage, automotive body control module configuration, medical infusion pump parameter backup, and smart meter firmware bootloader settings requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for M93C66-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 silicon solutions for automotive, industrial, and embedded applications with emphasis on reliability, longevity, and functional safety.

The M93Cxx series targets cost-sensitive, high-reliability embedded systems requiring simple, noise-immune serial EEPROMs with extended data retention-designed specifically for configuration, calibration, and identity storage in harsh or long-life environments.

FAQ

What is the function of the ORG pin on M93C66-WMN6P?

The ORG pin selects memory organization: when pulled high (or left unconnected), the device operates in 256-word (x16) mode; when pulled low, it operates in 512-byte (x8) mode. This determines address width and data bus width during READ/WRITE operations, and must be set before issuing any instruction. Incorrect ORG state causes misaligned addressing and invalid data access.

How does the READY/BUSY signal work during write operations?

When Chip Select (S) is high during programming (WRITE, ERASE, WRAL, ERAL), the Q pin outputs LOW (BUSY) until the internal cycle completes (~5 ms), then transitions HIGH (READY). The signal is valid only while S is asserted; it remains HIGH after completion until S goes low or a new start bit is detected. No external polling delay is needed-status is synchronous and deterministic.

Can M93C66-WMN6P be used with a 1.8 V microcontroller?

No-M93C66-WMN6P is the -W variant with 2.5 V to 5.5 V supply range. For 1.8 V operation, ST offers the M93C66-R series (e.g., M93C66-RMN6TP), which supports 1.8–5.5 V but shares identical pinout, instruction set, and timing. Using the -W part below 2.5 V violates absolute maximum ratings and risks unreliable operation or data corruption.

What happens if the Serial Clock (C) glitches during a WRITE instruction?

The on-chip clock pulse counter detects incorrect bit count between start bit and S falling edge and aborts the instruction. Memory contents remain unchanged, and no write occurs. This hardware-level error rejection eliminates need for software checksums or retry logic-critical for robust operation in electrically noisy industrial or automotive environments per DS1077 Rev 20 Section 7.