SanDisk iNAND Flash and microSD

Comparison of iNAND series technical specifications

The following table summarizes the key parameters of three iNAND products (based on the original document):

Model iNAND 7350 iNAND 7232 iNAND 7250

Capacity 32GB -256GB 16GB -128GB 8GB -64GB

Interface e.MMC 5.1 HS400 e.MMC 5.1 HS400 e.MMC 5.5 HS400

Package (mm) 8GB: 11.5 × 13 × 0.8

16GB: 11.5×13×0.9

32/64GB: 11.5×13×0.8/1.0

128GB: 11.5×13×1.0

256GB: 11.5×13×1.2 16GB: 11.5×13×0.9

32GB: 11.5×13×0.9

64GB: 11.5×13×1.0

128GB: 11.5×13×1.2 8GB: 11.5×13×0.8

16GB: 11.5×13×0.9

32GB: 11.5×13×1.0

64GB: 11.5×13×1.2

Technical highlights include 3D NAND, high-performance second-generation SmartSLC, 4K/UHD video optimization, industrial grade wide temperature range, and high reliability

OEM microSD card series: reliable edge storage and application performance

In addition to embedded flash memory, SanDisk also provides OEM customers with a rich line of microSD card products to meet the needs of storage expansion, edge device data recording, and mobile application performance improvement.

1. SanDisk Edge microSD card: 3D NAND driven edge storage

SanDisk Edge microSD card is a commercial grade storage card that uses 3D NAND technology to provide reliable and secure edge storage. It meets stringent safety, capacity, performance, and environmental requirements. The capacity range is from 16GB to 256GB, which can store up to 60 hours of full HD video (based on 256GB). This card is suitable for surveillance cameras, dashcams, drones, and other commercial applications. Its speed level is U3/V30 (video speed level 30), ensuring a continuous write speed of not less than 30MB/s, meeting the requirements of high-resolution video recording. The working temperature range is -25 ° C to 85 ° C, suitable for outdoor and vehicular environments.

2. SanDisk OEM A1 microSD Card: Breakthrough in Application Performance Level 1

The SanDisk OEM A1 microSD card is one of the first products in the industry to meet the application performance level 1 (A1) requirements of the SD Association 5.1 specification. The A1 standard defines the minimum requirements for random read and write performance: 1500 random read IOPS and 500 random write IOPS, while ensuring at least 10MB/s sequential performance. The card has a capacity of up to 256GB, allowing consumers to use microSD cards as internal storage for additional capacity, faster speeds, and a better smartphone experience. This is particularly important for entry-level and mid-range phones that do not support high built-in storage. In terms of performance, the maximum read speed is 95MB/s (256GB model), and the maximum write speed is 10MB/s (or higher, depending on capacity). The working temperature range is -25 ° C to 85 ° C.

Comparison of microSD card technical specifications

Product Edge microSD A1 microSD Standard microSD (Class 10) Standard microSD (Class 4)

Capacity 32GB -128GB (with 256GB and 200GB models available) 256GB, 200GB 8GB -128GB 8GB -64GB

Speed Class UHS-I U3 UHS-I U1/Class 10 UHS-I Class 4

Typical read-write (MB/s) 80/50 95/10 (256GB) or 80/10 40/10 20/5

NAND technology 3D NAND 12nm plane? 12nm 12nm

Working temperature -25 ° C~85 ° C -25 ° C~85 ° C -25 ° C~85 ° C -25 ° C~85 ° C

Main applications include monitoring, driving recorders, unmanned aerial vehicles, smartphones, internal storage expansion, universal storage, and basic storage

Note: Edge microSD uses 3D NAND for some capacity, while A1 card may use 12nm planar NAND (as indicated in the original text).

In depth interpretation of core technologies

1. e.MMC interface and HS400 mode

e. MMC is an embedded storage interface defined by the JEDEC standard, which integrates MMC interface, NAND flash memory, and controller into one package. HS400 (High Speed 400) is a double data rate mode defined by e.MMC 5.0/5.1, providing a theoretical interface speed of up to 400MB/s on an 8-bit bus. INAND 7350 and 7232 support HS400, ensuring compatibility with mainstream mobile application processors.

2. SmartSLC technology

SmartSLC is a dynamic storage conversion technology. Normally, NAND flash memory operates in TLC (3 bits per cell) or MLC (2 bits per cell) mode to reduce costs. When high-speed writing is required (such as recording 4K videos), SmartSLC temporarily switches some capacity to SLC mode (1 bit per unit), which can increase the writing speed several times. After the writing is completed, the data is rewritten back to the TLC/MLC area in the background. The second generation SmartSLC further optimizes conversion efficiency and lifespan management, making iNAND 7232 an ideal choice for mobile video creation.

3. 3D NAND flash memory

Traditional 2D NAND increases density by reducing the manufacturing process, but faces issues of leakage and interference. 3D NAND stacks storage units vertically, such as 32 layers, 64 layers, or even higher. The iNAND 7350 and Edge microSD cards use 3D NAND, which not only achieves a high capacity of 256GB, but also improves write durability and read interference tolerance, while reducing the cost per GB.

4. Application performance level A1

The A1 symbol introduced by the SD 5.1 specification aims to address the issue of insufficient random I/O performance when microSD cards were used as internal storage in the past. A1 requires a minimum of 1500 IOPS for random reads and 500 IOPS for random writes. The SanDisk A1 card meets this standard, allowing phone manufacturers to confidently design microSD card slots for expandable internal storage without sacrificing the smoothness of application startup and operation.