W25Q64JVSSIQ

The W25Q64JVSSIQ is a 64Mbit (8M x 8) SPI NOR Flash memory manufactured by Winbond Electronics, belonging to the SpiFlash family. It supports Standard SPI, Dual SPI, and Quad SPI interfaces with a maximum clock frequency of 133 MHz, achieving equivalent data rates of 266 MHz (Dual) and 532 MHz (Quad). The device operates from 2.7V to 3.6V with typical 3.3V supply.

The memory is organized as 32,768 programmable pages of 256 bytes each, with uniform 4 KB sectors, 32 KB and 64 KB blocks, and full-chip erase capability. There are 2,048 erasable sectors and 128 erasable blocks. Page program time is 3 ms max, and sector erase time is 100 ms typical. The device supports program/erase suspend and resume for real-time interrupt handling.

Advanced security features include a 64-bit unique ID per device, three 256-byte security registers with OTP lock, volatile and non-volatile status register bits, and individual block/sector write protection. Top/bottom and complement array protection modes are supported. The device also provides SFDP (Serial Flash Discoverable Parameters) and a QPI (Quad Peripheral Interface) mode for even faster command overhead.

Power consumption is 25 mA max active read current and less than 1 uA in power-down mode. The device is fabricated in 58 nm process technology with a minimum endurance of 100,000 program-erase cycles per sector and more than 20-year data retention. Operating temperature range is -40 to +85C. The 8-SOIC package (0.209 inch, 5.30 mm width) is AEC-Q100 qualified for automotive applications. RoHS compliant, ECCN 3A991.b.1.a. Product status: Active.

The W25Q64JVSSIQ operates as a serial NOR Flash memory accessed via the SPI bus:

1. SPI Interface Modes: The device supports three interface modes selected by commands. Standard SPI uses four signals (CLK, /CS, DI, DO). Dual SPI uses IO0 and IO1 for bidirectional 2-bit data transfer at 266 MHz equivalent. Quad SPI activates all four I/O pins (IO0-IO3) for 4-bit transfer at 532 MHz equivalent, dramatically reducing code shadowing and XIP access time.

2. Memory Array Access: Read operations begin with a command byte followed by a 24-bit address. In fast read modes, additional dummy clocks allow the pipeline to pre-fetch data. Sequential reads auto-increment the internal address counter within page, sector, or the entire array boundaries. Continuous read mode reduces command overhead to as few as 8 clocks per access.

3. Program and Erase: Page programming writes 1 to 256 bytes at a time. Erase operations support 4 KB sector, 32 KB block, 64 KB block, or full-chip erase. All program and erase operations require a preceding Write Enable (06h) command for safety. A program/erase suspend feature allows interrupting a long operation to read from a different area, then resuming.

4. Write Protection: Multiple protection levels include Status Register write protection (SRWD bit + /WP pin), individual block/sector locking via individual write protect registers, and OTP (One-Time Programmable) security register locking. The /WP pin hardware-protects the status register when SRWD=1.

5. Power Management: The device enters power-down mode via the Power Down (B9h) command, reducing current to <1 uA. Release from power-down takes 3 us typical. On power-up, the device defaults to Standard SPI mode with write disabled. 6. Reset: Both software reset (66h + 99h command sequence) and hardware reset (/RESET pin, available on select packages) restore the device to default state, useful for system recovery.