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JMicron Technology Corporation
Traded asGTSM: 4925
FoundedSeptember 2001; 17 years ago (2001-09)
Key people
Tim Liu (Chairman)
Tim Liu (President)
ProductsIntegrated circuits, bridge controllers

JMicron Technology Corporation (Chinese: 智微科技; pinyin: Zhìwēi Kējì) is a Taiwanese fabless technology design house based in Hsinchu, Taiwan. As a manufacturer of integrated circuits, they produce controller chips for bridge devices.[1]



The company was founded in September 2001 and its headquarters is in Hsinchu, Taiwan. The company also operates an advanced R&D center based out of Irvine, California, United States.

In 2002, the company begins development of their USB 2.0 to SATA bridge controller technology.[2]

JMicron begins developing SSD technology in 2006, launching their first generation SSD controller, the JMF601A/602A, towards the end of 2007.

JMicron's SSD controller is widely adopted by many SSD manufacturers such ASUS Eee PC, Corsair,[3] OCZ, and Transcend. JMicron was one of the first[4] companies to provide an SSD controller chip to these companies, allowing them to produce reasonably priced MLC SSDs.

2008 to Present[edit]

In early 2008, a write latency issue is discovered with the JMF601A/602A that occurs when system data is nearly full and the host continues to write data. Soon after, the company released the JMF601B/602B to address the write latency problem.[5] Also in 2008, JMicron showcases a number of peripheral products. This includes the JMB353, a hi-speed USB & 1394a to SATA II external HDD controller chip; this device is the first to feature an integrated 1394a PHY chip. Also included in the showcase is the JMB38x series, a PCIe to card reader & 1394 controller chip, the JMB211, a Gigabit Ethernet PHY controller chip, the JMB352, a hi-speed USB & eSATA to 2-port SATA II external HDD controller chip, and the JMB325, a 1- to 5-port SATA II port multiplier with hardware RAID.[6]

In 2009, the JMF612 is released, and sees popularity throughout 2010 in its use in a number of industry SSDs.[7] In particular, 2009 was a landmark year for JMicron in that the company achieved the top ranking as a supplier for external HDD and SATA-PATA bridge controllers, shipping roughly 35 million and 15 million units, respectively.[2]

In October 2010, JMicron was scheduled to list on the Taiwanese Gre Tai Securities Market (GTSM).[2] Also in 2010, a Gartner tandem research report reveals JMicron to be first in interface controller chip market share.[8] In 2010 stolen private keys certificates were used for digitally sign rootkit drivers in Stuxnet virus.[9][10]

After developing its own physical layer and high speed technology over the preceding years because of flat growth in the long term, JMicron diversifies from the base notebook and motherboard controller business. 2011 is characterized by JMicron winning orders from Western Digital and Samsung Electronics for JMicron's USB 3.0 HDD controller, with net sales projected to grow 10%.[11]

In late 2011, the JMF661 is released as a third generation JMicron SSD controller, and is shown to be an effective entry-level product. Shortly thereafter, in 2013, the JMF667 series is released as a 256 GB capacity, 512 MB DDR3 external cache SSD controller.[12] Analysis in 2013 reveals that SSD controller technology and high-speed transmission interface IC accounts for 29% and 67% of JMicron's sales, respectively.[2]

In June 2014, JMicron announced the JMF670 and JMF670H. Both are 4-channel SATA SSD controllers capable of supporting up to 512 GB of storage capacity. Production was to begin in July 2014. In the same announcement, they showcased the JMF810, a PCIe Gen II 2-lane controller, and the JMF811, a PCIe Gen II 4-lane SSD controller. These controllers are designed for speeds of up to 1.5 GB/s in sequential read and 1.2 GB/s in sequential write. Another announcement was the JMS577, which is a USB 3.0 to SATA VI Gb/s bridge controller. The company also showcased their USB 3.1 technology, which is expected to achieve data transmission speeds of 10 Gbit/s—doubling the speed of the previous USB Gen III controller.[13] Among these announcements included a single-chip, dual-port SATA III RAID/CLONE program within the JMS561/562/561U product line.[8]

Throughout 2014, JMicron's JMF667H was reviewed by a number of online review sites like Tom's Hardware, AnandTech, and TweakTown.

In June 2016, JMicron spun off its SSD division to Maxiotek Corporation, a Taiwan-based company designs and markets SSD controller products. Meanwhile, JMicron released the JMS576, its first USB-C USB 3.1 Gen 1 to SATA 6Gbit/s bridge controller.


Bridge Controllers[edit]

JM20329: Hi-Speed USB to SATA Bridge

USB 3.0[14]

  • JMS561: USB 3.0 to Dual SATA III with RAID
  • JMS561U: USB 3.0 to Dual SATA III with CLONE
  • JMS562: USB 3.0 & eSATA III to Dual SATA III with RAID
  • JMS567: USB 3.0 to SATA III 6 GB/s, 3.3 Vcc
  • JMS568: USB 3.0 to SATA III 6 GB/s, 2.5 Vcc
  • JMS578: USB 3.0 to SATA III 6 GB/s, 2.5 Vcc
  • JMS576: USB Type-C 3.1 Gen1 to SATA III 6 GB/s, 2.5 Vcc

USB 2.0[15]

  • JMB352: USB 2.0 & SATA II to Dual SATA II with RAID
  • JMB352U: USB 2.0 & SATA II to Dual SATA II Port Multiplier
  • JMB355: USB 2.0 & eSATA & 1394A/B to SATA II
  • JM20329: USB 2.0 to SATA (mask ROM)
  • JM20337: USB 2.0 to SATA & PATA
JMB363: Combined single-chip PCIe PATA/SATA controller

SATA to PATA bi-directional[16]

  • JMD330: Serial ATA (SATA to PATA)
  • JMH330/S: Serial ATA (PATA to SATA)

Port Multiplier/Selector and RAID[17]

  • JMB320: 1 to 2-port Serial ATA II Port Multiplier or 2 to 1-port Serial ATA II Port Selector
  • JMB321: 1 to 5-port Serial ATA II Port Multiplier or 5 to 1-port Serial ATA II Port Selector
  • JMB361: PCIe 1.0a x1 to 1x Serial ATA II and 1x PATA UDMA/100 channel[18]
  • JMB363: PCIe 1.0a x1 to 2x Serial ATA II and 1x PATA UDMA/100 channel[19]
  • JMB368: PCIe 1.0a x1 to 1x PATA UDMA/100 channel[20]
  • JMB390: 1 to 2-port Serial ATA II Port Multiplier & RAID-0/1/10 Controller
  • JMB393: 1 to 5-port Serial ATA II RAID-5 Controller
  • JMB394: 1 to 5-port Serial ATA II RAID-5 Controller with LCD Module (LCM) interfaces
  • JMB572: 1 to 2-port Serial ATA III Port Multiplier or 2 to 1-port Serial ATA III Port Selector
  • JMB575: 1 to 5-port Serial ATA III Port Multiplier or 5 to 1-port Serial ATA III Port Selector

Market Reception[edit]

When flash controllers were first offered to SSD manufacturers in 2008, JMicron's early JMF601 and JMF602 models were reported to have issues with write latency, causing a stuttering problem.[21][22] The performance problem was attributed to the small buffer size used in the controller.[23] After several corrective releases, JMicron released the JMF667H, which to date has received generally positive reviews, being cited as both competitive and budget-friendly[24] when used with the correct type of NAND.[25] For instance, when paired with Toshiba's A19 NAND, the JMF667H has been shown to be capable of achieving the following metrics: 500 MB/s for 128 KB sequential read, 450 MB/s for 128 KB sequential write, and reaching 80,000 4 KB IOPS for both random read and write.[26] The JMF667H has also been found to have very low power consumption, with active idle power consumption in the 0.2-0.4 W range depending on the capacity of the controller, as well as an average power consumption rating of 0.36-0.78 W when examined in PCMark 7.[26] Certain drives driven by the JMF667H controller, such as the Kingfast C-Drive F8, have achieved high scores on independent review sites—for example, 90% on TweakTown.[27]

See also[edit]


  1. ^ JMicron's solution/product list
  2. ^ a b c d JMicron Technology Corp
  3. ^
  4. ^ JMicron SSD Testing With A19, L85A & L85C Memory
  5. ^ Exclusive Interview With JMicron on SSD Controllers
  6. ^ JMicron new series of high-speed interface solutions will be coming Computex
  7. ^ JMicron JMF612 Solid State Drive Processor
  8. ^ a b JMicron Technology showcase a variety of storage controller chip in International Computer Show
  9. ^ Aleksandr Matrosov; Eugene Rodionov; David Harley & Juraj Malcho. "Stuxnet Under the Microscope" (PDF). Retrieved 24 September 2010.
  10. ^ Kim Zetter (23 September 2010). "Blockbuster Worm Aimed for Infrastructure, But No Proof Iran Nukes Were Target". Wired. Retrieved 4 November 2016.
  11. ^ [1]
  12. ^ 当今SSD主控里的非主流,JMicron历代主控回顾
  13. ^ JMicron introduces at Computex Taipei 2014 a series of PCIe and SATA SSD Controllers, new features for the USB 3.0 Storage Products, and the USB3.1 Storage Controller Solutions
  14. ^ JMicron's USB 3.0 Series Product Line
  15. ^ JMicron's USB 2.0 Series Product Line
  16. ^ JMicron's SATA to PATA Bi-Direction Series Product Line
  17. ^ JMicron's Port Multiplier/Selector & RAID Series Product Line
  18. ^ JMB361 datasheet
  19. ^ JMB363 datasheet
  20. ^ JMB368 datasheet
  21. ^ OCZ Once Again Slashes the Price of Core Series SSDs
  22. ^ G.Skill, Intel & Patriot SSD group test
  23. ^ Avoid SSDs with Jmicron's JMF602 Controller
  24. ^ Tweaktown: JMicron JMF667H Firmware Preview Testing with L85A, L85C and A19 Flash by Chris Ramseyer
  25. ^ JMicron JMF667H Reference Design (128GB & 256GB) Review by Kristian Vättö
  26. ^ a b JMicron Returns: The JMF667H Controller On Four Reference SSDs by Christopher Ryan
  27. ^ Kingfast C-Drive F8 Series 240GB SSD Review - Cheapest tested 240GB drive so far - Final Thoughts

External links[edit]