Winbond Electronics Corporation W25Q40EWSSIG TR

Overview

W25Q40EWSSIG TR from Winbond is a 4 M-bit (512 KB) serial NOR flash memory IC designed for code storage and execution in space-constrained embedded systems. It supports Standard/Dual/Quad SPI and QPI interfaces, operates from 1.65V to 1.95V, delivers up to 104 MHz clock rate (416 MHz equivalent Quad I/O), and features uniform 4 KB sectors, 100K program-erase cycles, and 20-year data retention.

For engineers reviewing the W25Q40EWSSIG TR datasheet, W25Q40EWSSIG TR pinout, W25Q40EWSSIG TR application, or W25Q40EWSSIG TR equivalent, key selection considerations include Quad Enable (QE) bit configuration for IO2/IO3 functionality, /WP and /HOLD pin behavior in SPI vs. Quad/QPI modes, sector-level hardware write protection, and compatibility with XIP (execute-in-place) boot architectures requiring fast read throughput.

Technical Context

The W25Q40EWSSIG TR implements a flexible SPI command architecture supporting four operational modes: Standard SPI (4-wire), Dual SPI (2 I/O lines), Quad SPI (4 I/O lines), and QPI (4-line instruction + 4-line data). Mode switching requires explicit Enter QPI (38h) and Exit QPI (FFh) commands, and Quad/QPI operation depends on non-volatile QE bit = 1 in Status Register-2.

Its memory array comprises 2,048 pages of 256 bytes each, organized into 128 erasable 4 KB sectors and 8 erasable 64 KB blocks. Erase/program suspend/resume capability enables concurrent background operations, while the 64-bit unique serial number and SFDP register support secure identification and configurable timing parameters.

Key Specifications

Pinout & Package

W25Q40EWSSIG TR is packaged in an 8-pin SOIC 150-mil (package code SN), with pin 1 marked by a dot or beveled corner. Pin assignments are identical for SOIC and VSOP variants.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar serial NOR flash applications.

Compared with MX25L4006EM1I-12G and S25FL004KAGMFI010, the W25Q40EWSSIG TR uniquely combines QPI instruction compression, JEDEC-standard SFDP, and guaranteed 20-year retention across full -40°C to +85°C range - making it optimal for thermally demanding, high-reliability XIP deployments.

Availability

W25Q40EWSSIG TR is available at Aetrix Electronics and suitable for bootloader storage, firmware OTA updates, secure key vaulting, audio prompt hosting, and sensor calibration logging requiring stable component supply across automotive, industrial, and medical design cycles.

Supply support for W25Q40EWSSIG TR 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

Winbond Electronics is a Taiwan-based semiconductor company specializing in specialty DRAM, mobile DRAM, and serial flash memory solutions for embedded, communications, and consumer markets.

The W25Q series targets resource-constrained embedded systems needing high-speed, low-voltage, secure code and data storage - with emphasis on XIP readiness, sector-level flexibility, and long-term reliability in extended temperature environments.

FAQ

What interface protocols does the W25Q40EWSSIG TR support, and how do they differ in implementation?

The W25Q40EWSSIG TR supports Standard SPI (4-wire), Dual SPI (2 I/O), Quad SPI (4 I/O), and QPI (4-line instruction + 4-line data). Standard SPI uses unidirectional DI/DO; Dual/Quad SPI repurpose /WP and /HOLD as IO2/IO3 when the non-volatile Quad Enable (QE) bit in Status Register-2 is set to 1. QPI requires explicit Enter QPI (38h) command and reduces instruction fetch to 2 clocks instead of 8, improving XIP efficiency. All modes share the same /CS, CLK, and VCC/GND pins.

How does the W25Q40EWSSIG TR handle write protection, and what are the hardware vs. software options?

The W25Q40EWSSIG TR provides layered write protection: hardware via /WP pin (active-low, disables Status Register writes when asserted), and software via Block Protect (BP2–BP0), Top/Bottom (TB), Sector/Block Protect (SEC), and Complement Protect (CMP) bits in Status Registers 1 and 2. The /WP pin is only functional when QE = 0; when QE = 1, it becomes IO2 and hardware protection must rely solely on register-based settings. Status Register Protect (SRP/SRL) bits further lock these configurations against accidental changes.

What is the significance of the Quad Enable (QE) bit in the W25Q40EWSSIG TR, and how is it configured?

The Quad Enable (QE) bit is a non-volatile bit in Status Register-2 that permanently enables Quad SPI and QPI modes by reassigning /WP and /HOLD pins to IO2 and IO3. It is factory-reset to 0 and must be set once using Write Status Register-2 (31h) after issuing Write Enable (06h). Once set, QE cannot be cleared without chip erase. This configuration is mandatory for any Quad or QPI operation and directly affects pin functionality and interface timing requirements in the host design.

Can the W25Q40EWSSIG TR be used for execute-in-place (XIP) applications, and what performance benefits does it offer?

Yes, the W25Q40EWSSIG TR is explicitly optimized for XIP use cases. Its Fast Read Quad I/O (EBh) instruction achieves up to 416 MB/s effective throughput (104 MHz × 4), enabling direct code execution without RAM loading. Combined with uniform 4 KB sectors and erase/program suspend/resume, it supports deterministic real-time firmware updates. The QPI mode further reduces instruction overhead, cutting latency for repeated function calls in boot-critical paths - a measurable advantage over standard SPI flash in automotive and industrial control firmware.

What packaging and environmental specifications apply to the W25Q40EWSSIG TR variant?

W25Q40EWSSIG TR is supplied in an 8-pin SOIC 150-mil package (SN code), RoHS-compliant and rated for industrial temperature range (-40°C to +85°C). It operates from 1.65 V to 1.95 V, draws ≤1 mA active current and <1 µA in power-down mode. The "TR" suffix denotes tape-and-reel packaging for automated assembly, and "IG" indicates lead-free, halogen-free construction meeting IPC/JEDEC J-STD-020 moisture sensitivity level 3 (MSL3) handling requirements.