SPI NOR Flash Memory ICs — W25Q, MX25L, GD25Q Series

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SPI NOR Flash Memory ICs — W25Q, MX25L & GD25Q Series SPI NOR flash memory ICs are the standard non-volatile storage solution for BIOS chips, router firmware, IoT devices, and embedded systems. Unlike NAND flash (used in SSDs and USB drives), NOR flash offers byte-addressable random read access, making it ideal for code execution (XIP — Execute In Place) and firmware storage. This collection covers the most widely used SPI NOR flash ICs from Winbond (W25Q series), Macronix (MX25L series), and GigaDevice (GD25Q series) — all in the standard SOP-8 package. Winbond W25Q Series (Most Popular) W25Q16 (2MB): Standard BIOS, basic router firmware, small embedded storage W25Q32 (4MB): Most common BIOS size, ESP8266 firmware + SPIFFS, standard router firmware W25Q64 (8MB): Larger BIOS images, ESP32 firmware + filesystem, higher-end routers W25Q128 (16MB): Large BIOS, Teensy 4.1 external flash, complex embedded applications W25Q512 (64MB): Maximum W25Q capacity — Teensy 4.1 audio sample storage, large data logging Macronix MX25L Series MX25L3206E (4MB): Pin-compatible W25Q32 alternative — widely used in older BIOS and router boards Breakout Modules CJMCU-2516 Module: W25Q16 on a 2.54mm breakout board — breadboard-friendly SPI flash for Arduino and ESP32 SPI Flash Selection Guide BIOS replacement: Match the exact part number on the original chip (W25Q32, MX25L3206, etc.) ESP8266 / ESP32: W25Q32 (4MB) for firmware + SPIFFS; W25Q128 (16MB) for large filesystem Teensy 4.1 external flash: W25Q128 (16MB) or W25Q512 (64MB) — solder to bottom of board Router firmware: Match original chip — most common are W25Q32, W25Q64, MX25L3206 Arduino SPI storage: CJMCU-2516 module (no SMD soldering required) All SPI flash ICs are new, original Winbond/Macronix/GigaDevice parts in SOP-8 packages. 100,000 erase cycles, 20-year data retention.