1.3 NAND Flash Types

NAND Flash devices come in several types, each offering a different balance of performance, cost, endurance and data retention. The main categories include SLC (Single-Level Cell), MLC (Multi-Level Cell), TLC (Triple-Level Cell) and QLC (Quad-Level Cell). These types differ in how many bits they store per cell—ranging from one in SLC to four in QLC—directly affecting their reliability and write endurance. In embedded systems, and especially in boot-critical applications, choosing the appropriate NAND Flash type is essential. For instance, devices like the SAM9X60 and SAM9X7 Series MPUs often use SLC NAND for ROM code booting due to its higher reliability and better error tolerance.

The characteristics of some types of NAND Flash devices are summarized below:

• SLC (Single-Level Cell): Higher endurance and reliability (lower error rates), suitable for industrial applications
• MLC (Multi-Level Cell): Higher density and lower cost, but reduced endurance and reliability (higher error rate)
• TLC (Triple-Level Cell): Used in consumer applications where writing endurance is less critical