Silicon Motion Announces SM2256 — World’s First 6Gb/s SSD Controller Supporting TLC NAND

Silicon Motion Technology Corporation, a world-leading designer and marketer of NAND flash controllers for solid-state storage devices, is announcing the SM2256 6Gb/s SSD controller.  The SM2256 represents the world’s first complete merchant ASIC/firmware SATA 6Gb/s controller supporting triple-level cell (TLC) 1x/1y/1znm NAND from all major NAND producers.

SM2256 SSD Controller

The SM2256 features Silicon Motion’s proprietary NANDXtend technology.  This state-of-the-art error detection and correction (ECC) engine offers three levels of error correction and data protection.  First, error correction occurs using Low Density Parity Check (LDPC) hard decoding with high-efficiency, low-power circuits to minimize power consumption.  Next, LDPC soft-decoding digital signal processing algorithms provide an extra level of error detection and correction by monitoring voltage thresholds.  Finally, on-chip RAID with page parity is used for recovering uncorrectable data.

SM2256 NANDXtend technology

Also, the NANDXtend technology helps maintain consistent data throughput, and provides an improved user experience — even as error bits increase over the life cycle of the NAND flash. The SM2256 is able to triple the number of program/erase (P/E) cycles for TLC NAND, extending the drive’s lifespan and enabling consistent high performance, improved reliability,  and more cost-effective solid-state storage devices.

SM2256 NAND support

According to Wallace Kou, President and CEO of Silicon Motion, “We are excited to be the only merchant controller supplier today to offer a SATA 6Gb/s SSD controller with complete ASIC and firmware for TLC NAND.  Our SM2256 supports the broadest range of NAND flash, including 1x/1y/1znm TLC NAND and the upcoming 3D NAND from all the major NAND suppliers, allowing SSD OEMs to deliver the most advanced, cost-effective and reliable SSDs in the market.”

SM2256 TLC usage ratio rise

The industry-leading capabilities and technologies featured in Silicon Motion’s SM2256 include:

  • Proprietary NANDXtend error-correction and data protection technologies to triple P/E cycles for TLC SSD devices
  • Supports the latest 1x/1y/1znm MLC and TLC flash, enabling cost-optimized, high capacity consumer SSDs
  • Extensible to support future 3D MLC/TLC NAND
  • Supports ONFI 3.0, Toggle 2.0 and asynchronous NAND
  • Ultra high performance (with 256GB SSD utilizing Toshiba A19 TLC NAND) :

                            * Sequential read — 524MB/s

                             *Sequential write — 400MB/s

                             *4K Random read (QD=32) — 90,000 IOPS

                             *4K Random write (QD=32) — 70,000 IOPS

  • Ideal for consumer SSDs — targeting ultrabooks, laptops, tablets and HDD replacement
  • Incorporates latest security protocols — AES256, Trusted Computing Group (TCG) and Opal full-drive encryption compliant
  • Supports both commercial (0 to 70 degrees centigrade) and industrial (-40 to 85 degrees centigrade) requirements

SM2256 data

Gregory Wong, President of Forward Insights, observes that “NAND flash memory is transitioning to TLC technology in an effort to improve the affordability and increase adoption of solid-state drives.  Solutions such as Silicon Motion’s SM2256 controller enable systems manufacturers to leverage TLC technology in cost-effective SSD products without compromising performance, endurance or reliability,”

SM2256 client SSD by NAND type forecast

Another pertinent observation comes from Michael Yang, senior principal analyst at IHS iSUPPLi:  “We expect TLC SSDs to account for more than 40% of all client SSD shipments in 2015.  The combination of cost effective TLC NAND and new controllers like Silicon Motion’s SM2256 will help drive this level of adoption.”

SM2256 block diagram

Silicon Motion is presently sampling the SM2256 SSD controller with multiple customers and multiple design-ins underway, and complete design kits are currently available.  Mass production is anticipated to begin in Q4 of 2014.


Visit Silicon Motion at the 2014 Flash Memory Summit from 8/5 through 8/7, at the Santa Clara Convention Center in Santa Clara, California.  You will find Silicon Motion at booth #615 and booth #617.