Cirrus Logic

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Cirrus Logic Inc. is a fabless semiconductor company that specializes in analog, mixed-signal, and audio DSP integrated circuits (ICs). Cirrus Logic has its headquarters in Austin, Texas. The company's audio processors and audio converters feature in many professional audio and consumer entertainment products, including smartphones, tablets, portable media players, automotive entertainment systems, home-theater receivers, televisions and docking stations. Cirrus Logic's analog mixed-signal converter chips are also used in a wide variety of energy-related applications, including its new line of LED controllers for the incandescent light-bulb replacement market, as well as energy-measurement chips for applications such as digital utility meters.

Dr. Suhas Patil founded the company as "Patil Systems, Inc." in Salt Lake City in 1981; it adopted the name "Cirrus Logic" when it moved to Silicon Valley in 1984.

Cirrus Logic has more than 1,000 patents and more than 600 products serving more than 2,500 end-customers globally.


Patil Systems, Inc., was founded in Salt Lake City in 1981 by Dr. Suhas Patil, in 1983 the company was reorganized by Dr. Patil, Kamran Elahian, and venture capitalist Fred Nazem, whose firm, Nazem and Company provided the company's first/start-up round of financing. Later the company was renamed as Cirrus Logic when it moved to Silicon Valley in 1984 to focus on solutions for the growing PC components market. Michael Hackworth was named president and chief executive officer in January 1985, and served as CEO until February 1999. It joined the Nasdaq market listing in 1989 (symbol: CRUS). Cirrus Logic acquired Crystal Semiconductor, a supplier of analog and mixed-signal converter ICs, in 1991. In the early 1990s, Cirrus Logic became a supplier of PC graphics chips, audio converters and chips for magnetic storage products. David D. French joined Cirrus Logic, Inc., as president and chief operating officer in June 1998 and was named chief executive officer in February 1999. Soon after joining the company, through an acquisition strategy Mr. French repositioned the company into a premier supplier of high-performance analog and digital processing chip solutions for consumer entertainment electronics and soon afterwards, Mr. M. Yousuf Palla joined as Vice President of Operations and Manufacturing, contributing further to its success. In June 2005, Cirrus Logic sold its video products operation to an investment firm, creating privately owned Magnum Semiconductor. After French resigned in March 2007, Jason Rhode, formerly the vice president and general manager of Cirrus Logic's Mixed Signal Audio Division, was named president and CEO in May 2007. Today, Cirrus Logic is focused on its high-precision technologies for digital signal processing components for audio and energy markets. In 2014 Cirrus Logic bought Wolfson Microelectronics for £291 million.

Timeline of key events

  • 1981 – Patil Systems Inc. is founded in Salt Lake City by Dr. Suhas Patil. Company focuses on IC solutions for the growing PC components market.
  • 1984 – Patil Systems Inc. renamed Cirrus Logic and moves headquarters to Silicon Valley
  • 1989 – Company goes public and is listed on the Nasdaq exchange under the ticker symbol CRUS.
  • 1991 – Cirrus Logic acquires Crystal Semiconductor, a supplier of analog and mixed-signal converter ICs.
  • 1992 - Cirrus Logic Completes Deal for Acumos Inc.
  • 1998 – Cirrus Logic exits from the PC graphics card business
  • 1998 – David D. French joins company as president and chief operating officer in June and becomes chief executive officer in February 1999. In the fall, company spins out its communication business unit.
  • 2001 – Cirrus Logic announces plan to begin exit from magnetic storage chip business.
  • 2001 – Cirrus Logic acquires several start-up companies with technologies in video decoding, video encoding, wireless networking, and networked digital audio.
  • 2003 – Cirrus Logic closes wireless networking operations.
  • 2005 – Cirrus Logic sells video product assets to investment firm, creating Magnum Semiconductor (company maintains minority equity position).
  • 2007 – Jason Rhode, formerly vice president and general manager of Cirrus' Mixed-Signal Audio division, is named president and chief executive officer, replacing French who resigned in March. In July, Cirrus Logic acquires Apex Microtechnology, a provider of high-power products for industrial and aerospace markets. Cirrus Logic acquires audio chip company Tripath after they went bankrupt.
  • 2011 – Cirrus Logic is named to the Great Place to Work Institute's list of top small and medium-sized companies to work for in America, placing at #24. The company is also named by the Austin American-Statesman as the top Central Texas employer.
  • 2012 – Cirrus Logic appears at #9 on the Great Place to Work Institute's list of top small and medium-sized companies to work for in America, jumping 16 places compared to the 2011 listing. Cirrus Logic co-founder and chairman of the Board Michael Hackworth passes away in April. Company sells its hybrid product line in Tucson, Ariz., to a group of investors, creating Apex Microtechnology as a stand-alone company once again. In November, the company announces that it is moving its remaining product line team in Tucson to its Austin headquarters.

Graphics history

In the early 1990s, Cirrus Logic was a supplier of low-cost PC graphics chips. Cirrus' Microsoft Windows 2D GUI accelerators (GDI) were among the fastest in the low-end market-segment, outperforming competing VGA-chips from Oak Technologies, Trident Microsystems, and Paradise (Western Digital). For example, the Cirrus GD5422 (1992) supported hardware acceleration for both 8-bit color and 16-bit color. It was one of the lowest-priced SVGA controllers to support both.

By the mid-1990s, when PC's had migrated to the PCI bus, Cirrus had fallen behind S3 and Trident Microsystems. When the announced release date of the GD5470 "Mondello" came and went, Cirrus's reputation in desktop PC-graphics suffered. Mondello development took a back seat to the GD5464 which was near completion and proved to be a much faster design with the use of Rambus. (Because of this Mondello never got off the ground)

The company's final graphics chips, the GD546x "Laguna" series of PCI/AGP 3D-accelerators, were novel in that they were one of the few video cards to use Rambus RDRAM. The patented use of tiled memory used by the GD546x chips is still used by nearly all graphics processors today. However, like many other 2D/3D chips at the time were gate limited by the process technology available at the time, the feature set of perspective-correct texture mapping, bilinear filtering, single-pass lighting, gouraud shading, and alpha blending, was incomplete compared to the next generation of 3D chips. The GD546x family was limited by CPU processing at the time, CPU's could not feed it enough triangles which was the real performance block. The raw processing power of the GD546x was nearly 2.5 million 25 pixel triangles per second, much faster than competitors.

When Intel announced they were entering the 3D market with the i740 Cirrus Logic exited the market, which at the time for Cirrus Logic was worth 500 million dollars annually. (Intel didn't catch up in performance for many years, the i740 was not widely accepted and did not win any major designs).

Emulated Cirrus Logic graphic cards are used in emulators. QEMU emulate the Cirrus CLGD 5446 PCI VGA-card, which is also emulated by the Xen-HVM, KVM and Bochs (which in addition also emulates the CL-GD5430 ISA card).


  • CL-GD410 + 420 – ISA SVGA chipset, Video 7 VEGA VGA (1987)
  • CL-GD510 + 520 – ISA SVGA "Eagle II" chipset, known for 100% CGA emulation. (1988)
  • CL-GD5320 – ISA SVGA chipset. (1990)
  • CL-GD5401 – ISA SVGA chipset, also known as Acumos VGA (AVGA1)
  • CL-GD5402 – ISA SVGA chipset, also known as Acumos VGA (AVGA2)
  • CL-GD5410 – ISA SVGA chipset, Low-to-mid-end DRAM-based cards (accelerated), some laptop chipsets. Known for integrating graphics card components into one chip (built-in RAMDAC and clock generators) at an early point. (1991)
  • CL-GD5420 – ISA SVGA chipset, highly integrated (15 bit RAMDAC + PLL), 1 MB.
  • CL-GD5421 – ISA SVGA chipset, highly integrated (15/16 bit RAMDAC + PLL), 1 MB.
  • CL-GD5422 – Enhanced version of the 5420 (32-bit internal memory interface, 15/16/24 bit RAMDAC. An ISA video card carrying this chipset offered 1280×1024 interlaced max resolution
  • CL-GD5424 – VLB version of the 5422, but resembles the 5426 in some respects.
  • CL-GD5425 – True color VGA controller w/ TV out.
  • CL-GD5426 – Hardware BitBLT engine. ISA bus and VLB up to 2 MB of memory.
  • CL-GD5428 – Enhanced version of the 5426. Faster BITBLT engine.
  • CL-GD5429 – Enhanced version of the 5428; supports higher memory clock and has memory-mapped I/O.
  • CL-GD5430 – Similar to 5429, but with 543x core (32-bit host interface).
  • CL-GD5434 – Alpine family chip with 64-bit internal memory interface. Only supports 64-bit mode if equipped with 2 MB of video memory; commonly equipped with 1 MB, extendable to 2 MB.
  • CL-GD5436 – An optimized 5434.
  • CL-GD5440 – 5430 with motion-video acceleration. (CL-GD54M40 has integrated filters.)
  • CL-GD5446 – 64-bit Alpine VisualMedia accelerator. 2D-only; adds motion-video acceleration to the CL-GD5436.
  • CL-GD546X – The Laguna VisualMedia family of 2D, 3D, and video accelerators. '64 and '65 include 3D acceleration. (PCI, AGP). These chips use a single channel of RDRAM memory, providing up to 600 MB/s bandwidth. The '62 lacks 3D acceleration. All include a BitBLT engine, video windows, and 64×64 hardware cursor.
  • CL-GD5480 – 64-bit Alpine accelerator with 100 MHz SGRAM


  • CL-GD610 + 620 – (1989)
  • CL-GD6420/6440 Used in some laptops, similar to older Cirrus chipsets (5410/AVGA2).
  • CL-GD6205/6215/6225/6235 – Compatible with the 5420.
  • CL-GD7541/7542/7543/7548 – Compatible with the 5428/3x.