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Zilog, Inc.
Company typeSubsidiary
Founded1974 (1974)
United States
Number of employees
174 (2009)[1]

Zilog, Inc. is an American manufacturer of microprocessors, microcontrollers, and application-specific embedded system-on-chip (SoC) products.

Founded in 1974 by Federico Faggin and Ralph Ungermann, who were soon joined by Masatoshi Shima, who had all left Intel after working the 4004 and 8080 microprocessors. The company's most famous product is the Z80 microprocessor, which played an important role in the evolution of early computing. Software-compatible with the Intel 8080, it offered a compelling alternative due to its lower cost and increased performance, propelling it to widespread adoption in video game systems and home computers during the late 1970s and early 1980s.

The name, pronounced with a long "i" (/ˈzlɒɡ/), is an acronym of Z integrated logic, also thought of as "Z for the last word of Integrated Logic".


Zilog was started in California in 1974 by Federico Faggin and Ralph Ungermann,[2][3] who both left Intel after working on the 4004 and 8080 microprocessors and custom chips. Masatoshi Shima, who also worked with Faggin on the 4004 and 8080, joined Zilog in 1975.[4] Ungermann had a falling-out with Exxon and left Zilog in 1978.[5]

On January 1, 1979, Zilog released the first issue of their comic book Captain Zilog, which featured the Z8000 computer.[6] The Z8000, introduced that year, was the company's first 16-bit microprocessor.[7]

The company became a subsidiary of Exxon in 1980. Exxon initially acquired 51 percent of the company before buying it outright;[8] however, the management and employees bought it back in 1989, led by Edgar Sack.[9]

Zilog's iconic 8-bit processor, the Z80. Pictured is one of the first Z80s ever made.

Zilog went public in 1991, but was acquired in 1998 by Texas Pacific Group for $527 million.[10] Curtis Crawford replaced Sack and changed the company's direction towards 32-bit data communications processors.

In 1999, Zilog acquired Production Languages Corporation for an unspecified amount less than $10 million.[11]

Bonds were sold against the company to fund the new developments, but after the Internet bubble burst in 2000 and the resultant reduction in customer demand for such products, Curtis Crawford was replaced by James (Jim) Thorburn, who reorganized the company under Chapter 11 bankruptcy in late 2001 and refocused it on the 8- and 16-bit microcontroller market.

Earliest logo of Zilog
Earliest logo of Zilog
Logo of Zilog introduced in the 1990s
Logo of Zilog introduced in the 1990s

Jim Thorburn led Zilog back into profitability, and by FY 2007, Zilog had $82 million in sales. During this time, the company developed the Z8 Encore! 8-bit Flash MCU and ZNEO 16-bit Flash MCU product families. In February 2007, Zilog hired Darin Billerbeck to replace Jim Thorburn as president and CEO.

The last year Zilog introduced any new 8-bit microcontroller products was 2007. With no new product road map, FY2008 sales fell 20% to $67.2 million. Sales fell 46% in FY2009 to $36.2 million.[citation needed]

In January 2008, Zilog declined an unsolicited proposal made by Universal Electronics Inc. to acquire the company.[12]

On February 19, 2009, Zilog announced that it had sold off its 8-bit Crimzon Universal Remote Control infrared microcontroller product line, as well as its ARM9 32-bit microcontrollers, including the Zatara security microcontrollers and 15 patents, to Maxim Integrated Products. Remote control manufacturer Universal Electronics Inc. purchased all of Zilog's software and intellectual property assets related to Zilog's universal remote control business, including all ROM code, software, and database of infrared codes.[13] Zilog sold these assets for $31 million cash.

In December 2009, IXYS Corporation bought the company for $62.4 million in cash, which was significantly below the market valuation of Zilog's stock at the time.[14][15] Details of the acquisition have been under investigation.

A May 1976 advertisement for the Zilog Z-80 8-bit microprocessor

Since early 2010, Zilog has refocused on the industrial and consumer markets for motion detection, motor control, RF wireless and embedded security applications, and is currently producing a number of reference designs that integrate its 8- and 16-bit microcontrollers with IXYS power management products.

In February 2012, Zilog announced the release of its Z8051 family of microcontrollers and tool sets to fill a vacancy in the developer market for 8051 cores that was created when chip-maker NXP Semiconductors exited the 8051 market. Later that year, Zilog announced its ZGATE Embedded Security solution, which incorporates its eZ80F91 MCU and TCP/IP stack with an embedded firewall to offer protection against cyber threats and attacks at the chip level.

In August 2017, Zilog and its parent IXYS Corporation were acquired by Littelfuse Inc in exchange for $750 million in cash and stocks.[16][17]



The Z80(i) is an improved implementation of the Intel 8080 architecture, with substantial extensions to the register model and instruction set and with added hardware interface features. At introduction, the Z80 was faster, more capable, and much cheaper than the 8080. Alongside the 6502, the Z80 was one of the most popular 8-bit processors for general purpose microcomputers and other applications from the late 1970s well into the 1980s, and while modern CMOS versions of the 6502 are still in production and use today, the Z80 was discontinued in 2024.[18] The Z80 CPU was used in the Sinclair ZX80, ZX81, ZX Spectrum and the Amstrad CPC home computers as well as the MSX architecture and the Microbee and Tandy TRS-80 (models I, II, III, 4, and others). The CP/M-80 operating system (and its huge software library featuring hits like WordStar and dBase) was known to be the Z80 disk operating system, and its success is partly due to the popularity of the Z80. The 1985 Commodore 128 added a Z80 to the Commodore 64 hardware allowing it to run CP/M software; the Digital Equipment Corporation Rainbow 100 similarly added a Z80 to an Intel 8088-based MS-DOS computer to enable the machine to run both MS-DOS and CP/M software natively.

The Z80 was a common choice for creators of video games during the Golden age of arcade video games, with a Z80 powering Pac-Man,[19] dual Z80s in Scramble,[20] and three in each Galaga machine.[21] It was the central processor for the ColecoVision game console (1982) and Sega's Master System (1986) and Game Gear (1990).

In the 1990s, the Z80 was the CPU of the Texas Instruments graphing calculator series, as well as being used as the secondary/support CPU in the Sega Genesis (most typically used for sound[22]).

Other chips

After the Z80 Zilog introduced the 16-bit Z8000 and 32-bit Z80000 processors, but these were not particularly successful, and the company refocused on the microcontroller market, producing both basic CPUs and application-specific integrated circuits/standard products (ASICs/ASSPs) built around a CPU core. As well as producing processors, Zilog has produced several other components. One of the most famous was the Zilog SCC serial communications controller as found on early Apple Macintosh, Sun SPARCstations and SPARCservers up to the SPARCstation 20.

Zilog also formed a Systems Division, which designed the Zilog System 8000, a Z8000- or Z80000-based multiuser computer system running a Unix derivative called ZEUS (Zilog Enhanced UNIX System).[23][24]

Zilog attempted to enter the 32-bit microcontroller market in February 2006 with the demonstration of ARM9-based Point-Of-Sale (POS) microcontroller product line.[25][26] The final product was released in 2007 called Zatara.[27] Sales were disappointing and the entire ARM9 series was sold to Maxim Integrated Products in 2009.

Zilog also produced Zdots single board computers. It includes Zilog eZ80AcclaimPlus controller, 1MB flash memory, 512KB SRAM, 10BaseT Ethernet Controller, IrDA transceiver, 2 x 60-pin system expansion interface with full MPU bus/control signals, RJ-45 Ethernet connector.[28] Motion detection version includes Z8 Encore! XP MCU.[29]

Product list

Microprocessor families

Microcontroller families

Communication controllers

Motion detection

Digital signal processor

TV controllers

Line 21 decoders

Single board computers


Local area networking

See also


  1. ^ "Zilog Inc 10-K". March 2009. Archived from the original on 2013-11-13.
  2. ^ "ZILOG Oral History Panel on the Founding of the Company and the development of the Z80 Microprocessor" (PDF).
  3. ^ "9.6 Zilog Ungerman-Bass in Brief". Archived from the original on 2021-11-20. Retrieved 2022-04-04.
  4. ^ Liebson, Steven (2019-02-19). "In Memoriam: Dr. Bernard Peuto, Architect of Zilog's Z8000 and Z8". EEJournal. Retrieved 2022-08-15.
  5. ^ "Ralph Ungermann | History of Computer Communications". Archived from the original on 2023-02-04. Retrieved 2023-03-30.
  6. ^ Captain Zilog!. Lou Brooks, Joe Kuber. U.S.: Zilog, Inc. 1979.((cite book)): CS1 maint: others (link)
  7. ^ Lot, Chris (2022-08-21). "Clover Computer: A Modern Z8000 CP/M Machine". Hackaday. Retrieved 2022-09-01.
  8. ^ "The Time Exxon Went into the Semiconductor Business (And Failed)". The Atlantic. 17 May 2013.
  9. ^ "COMPANY NEWS; Zilog Team Seeks Company". The New York Times. 15 June 1989.
  10. ^ "Zilog Agrees to Be Acquired for $527 Million". The New York Times. 1997-07-22. ISSN 0362-4331. Retrieved 2022-08-15.
  11. ^ "Zilog acquires software-core developer Production Languages Corp". EETimes. 1999-12-14. Retrieved 2022-08-22.
  12. ^ "Zilog Press Release (February 4, 2008): "Zilog Board of Directors Declines Universal Electronics Inc.'s Unsolicited Proposal"".[permanent dead link]
  13. ^ "Zilog Sells Off Two Product Lines (February 19, 2009)".
  14. ^ "SEC filing: IXYS and Zilog merger".
  15. ^ "Zilog Acquired by IXYS".
  16. ^ "IXYS Corp. agrees to be bought by Littelfuse Inc. in $750 million cash and stock deal". Silicon Valley Business Journal. August 28, 2017. Retrieved January 10, 2018.
  17. ^ "Littelfuse buys Ixys for $750m". Electronics Weekly. 2017-08-29. Retrieved 2017-09-19.
  18. ^ "The End of an Era: Zilog Discontinues the Z80 Microprocessor". 2024-04-30. Retrieved 2024-05-29.
  19. ^ Zilog at the Killer List of Videogames
  20. ^ Zilog at the Killer List of Videogames
  21. ^ Zilog at the Killer List of Videogames
  22. ^ The Z80 in the Genesis has access to its own dedicated 8 KB of RAM, the sound hardware, the controller ports, the video chip (VDP) (which contains the PSG sound generator), the cartridge slot, the expansion interface, and other Genesis hardware registers, so this Z80 is versatile, even to the point that it can be used for general computation. The Master System emulation mode of the Genesis uses the Z80 to run the game software while the MC68000 CPU is effectively stopped; this is how Master System games run on the Genesis through the Power Base Converter, which has barely any electronics and is almost a purely passive wiring adapter. In principle, software on a Genesis cartridge (or on Sega CD media) could use the Z80 as the main CPU and let the 68000 serve as a support CPU: the functionality of the Z80 in the Genesis is really that general and flexible. (technical information source: Sega Genesis Programming Manual)
  23. ^ "ZILOG Z8000". Retrieved 2008-04-22.
  24. ^ Fiedler, Ryan (October 1983). "The Unix Tutorial / Part 3: Unix in the Microcomputer Marketplace". BYTE. p. 132. Retrieved 30 January 2015.
  25. ^ ZiLOG(R) Unveils 32-Bit ARM-9(R) Application-Specific Strategy to Focus on Security and Point-of-Sale Markets[permanent dead link]
  26. ^ New ZiLOG ARM9 Microcontroller Product Line
  27. ^ Zilog Leads the Secure Transactions Market with New 32-bit High Security Zatara(TM) Series ARM(R) Core Based ASSP[permanent dead link]
  28. ^ "Zilog Zdots eZ80F91 Module". Archived from the original on 2016-05-07. Retrieved 2009-03-28.
  29. ^ Zilog ePIR Enhanced Motion Detection ZDOTS Single Board Computer Bolsters Energy Management For Vending And Other Applications Back
  30. ^ "Zilog Z-80 Microcomputer System". Centre for Computing History. Retrieved 5 May 2023.
  31. ^ "Zilog MCZ-1 Series Microcomputer System". 1977. Retrieved 5 May 2023.
  32. ^ "Zilog MCZ 1/20 Z80 system". Retrieved 5 May 2023.
  33. ^ "Your gateway to the future" (PDF). RM Nimbus Museum. Zilog. Retrieved 5 May 2023.