What is SPI NAND?

What is SPI NAND?

Basic IC Knowledge: In the field of embedded systems, NOR Flash and NAND Flash are familiar storage devices. Early NOR Flash used a parallel interface, where data and address lines were arranged side by side on the IC pins. Due to incompatibilities between parallel NOR Flash with different capacities (due to varying numbers of data and address lines) and the large package size occupying significant PCB space, SPI (Serial Peripheral Interface) NOR Flash gradually replaced parallel NOR Flash.

SPI NOR Flash: SPI NOR Flash achieves pin compatibility across different capacities and uses smaller package forms (e.g., SOP8), quickly becoming the mainstream in the market. Many people now refer to NOR Flash simply as SPI Flash due to its widespread adoption.

NAND Flash: NAND Flash, on the other hand, uses address-data line multiplexing and adheres to unified interface standards (x8 bit or x16 bit), allowing for compatibility across different capacities without significant issues. Consequently, the packaging and interface forms of NAND Flash have remained largely unchanged over the years.

Emergence of SPI NAND: With increasing demands for smaller, cost-effective solutions and compact products, SPI NAND Flash has gained attention from engineers. SPI NAND Flash combines the high-density storage of NAND Flash with the smaller, more efficient serial interface of SPI, offering a promising solution for modern design needs.

Advantages of SPI NAND Flash:

Cost Reduction: Using SPI NAND Flash allows the MCU (Microcontroller Unit) to avoid the need for a traditional NAND controller, requiring only an SPI interface, which reduces the cost of the main controller.

Smaller Package Size: SPI NAND Flash uses an LGA-8 package, which has fewer pins and is much smaller than traditional NAND Flash packages like TSOP48. This results in simpler PCB layout, reducing PCB size and layer count, meeting miniaturization needs and lowering product costs.

Performance Considerations: Does SPI NAND Flash compromise on performance compared to traditional NAND Flash?

To illustrate, let’s consider the ATO Solution's 1Gb SPI NAND Flash model, ATO25D1GA-10ED. It is the world's first single-die SPI NAND Flash. SPI NAND Flash essentially combines NAND Flash and an SPI Controller on a single die. ATO Solution ensures stability and consistency by integrating both components into one wafer, providing better consistency and stability in the SPI NAND Flash products they manufacture. This integration helps avoid issues with varying controller drivers.

Additionally, ATO Solution has full in-house design capabilities for NAND Flash, and the NAND die used in their SPI NAND Flash is SLC (Single-Level Cell), which offers up to 100,000 program/erase cycles and a storage life of over 10 years. The product also includes ECC (Error Correction Code) to assist in managing the Flash more effectively.

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