NAND Flash 101 - An Introduction to NAND Flash and How to Design It In to Your Next Product

Nov 1, 2026

Uploaded by Jiven

This technical note introduces NAND Flash for embedded systems, explaining why designers are moving from NOR Flash toward NAND for higher density and lower cost. It outlines core hardware concepts such as blocks, page/byte programming granularity, erase behavior, and limits tied to program/erase cycles. It also covers reliability approaches including wear leveling, bad-block management, and the system-level shadowing technique for read/write access, plus an overview comparison of NAND versus NOR cells.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages27

Reading Time1 h 8 min

AccessFree to download

Introduction

Flash Basics

NAND Flash Device Structure

Erase and Program Fundamentals

Reliability and Longevity Techniques

NAND vs. NOR Comparison

Advantages of Each Device

Technical Note NAND Flash 101: An Introduction to NAND Flash and How to Design It In to Your Next Product Introduction This technical note discusses the basics of NAND Flash and demonstrates its power, density, and cost advantages for embedded systems. It covers data reliability and methods for overcoming common interface design challenges, focusing on the actual hardware and software components necessary to enable designers to build complete and functional subsystems. Embedded systems have traditionally utilized NOR Flash for nonvolatile memory. Many current designs are moving to NAND Flash to take advantage of its higher density and lower cost for high-performance applications. Figure 1 shows how demand for NAND Flash has been driven primarily several major markets—solid state drives, mobile phones, Flash memory cards, USB Flash drives and MP3/PMP players. As the quest has continued for lower-power, lighter, more robust products, NAND Flash has become the leading storage choice for a broad range of applications. It meets the storage requirements of many consumer storage, audio, and video products far better than a hard drive—particularly in lower-capacity applications (8GB or less). Figure 1: Major Markets Driving NAND Flash Mi l l ion GB 70,000 60,000 50,000 40,000 30,000 20,000 10,000 0 Other Solid State Drives Digital Video Camcorders Personal Navigation Devices Digital Still Cameras Mobile Phones MP3/PMP Players USB Flash Drives Flash Memory Cards Source: Forward Insights, NAND Quarterly Insights Q3/09, [www.forward-insights.com/](www.forward-insights.com/)[ ](www.forward-insights.com/)[Report No. FI-NFL-NQI-Q309 September 2009](Report No. FI-NFL-NQI-Q309 September 2009), accessed 4/14/2010; used with permission. PtDnF29:1099_0n_f8241015f6-0RSvouBrc/:10090E0N5aef8245f3bf 1 Micron Technology, Inc. , reserves the right toc©h2a0g6eMpircoroucTscor shnopleocgyif,icIanionAlsl wrigithhtous rnoserceed .. Products and specifications discussed herein are for evaluation and reference purposes only and are subject to change by Micron without notice. Products are only warranted by Micron to meet Micron’s production data sheet specifications. All information discussed herein is provided on an “as is” basis, without warranties of any kind. Flash Basics TheNAND Flash device discussed in this technical note is based on a 2Gb asynchronous SLC device and its parameters (unless otherwise noted). Higher density devices and other more advanced NAND devices may have additional features and different parameters. The NAND Flash array is grouped into a series of blocks, which are the smallest erasable entities in a NAND Flash device. ANAND Flash block is 128KB. Erasing a block sets all bits to 1 (and all bytes to FFh). Programming is necessary to change erased bits from 1 to 0. The smallest entity that can be programmed is a byte. Some NOR Flash memory can perform READ-While-WRITE operations. Although NAND FLASH cannot perform READs and WRITEs simultaneously, it is possible to accomplish READ/WRITE operations atthe system level using a method called shadowing. Shadowing has been used on personal computers for many years to load the BIOS from the slower ROM into the higher-speed RAM. There is a limitto the number of times NAND Flash blocks can reliably be programmed and erased. Nominally, each NAND block will survive 100,000 PROGRAM/ERASE cycles. A technique known as wear leveling ensures that all physical blocks are exercised uniformly. To maximize the life span of a design, it is critical to implement both wear leveling and bad-block management. Figure 2 shows a comparison of NAND Flash and NOR Flash cells. NAND efficiencies are due in part to the small number of metal contactsin theNAND Flash string. NAND Flash cell size is much smaller than NOR Flash cell size—4F2 compared to 10F2—because NOR Flash cells require a separate metal contact for each cell. PtDnF29:1099_0n_f824101

FAQs

Why are embedded system designs shifting from NOR Flash to NAND Flash?

NAND Flash offers higher density and lower cost, making it suitable for high-performance storage needs and many consumer devices.

What is the smallest erasable unit in NAND Flash, and what happens during erase?

NAND Flash is organized into blocks, and a block is the smallest erasable entity. Erasing a block sets all bits to 1 (and all bytes to FFh).

How does wear leveling improve NAND Flash reliability over time?

Wear leveling ensures physical blocks are exercised uniformly, helping maximize design life by mitigating uneven program/erase wear.

Nov 1, 2026

Uploaded by Jiven