Hans Camenzind

Hans Camenzind, designer of the 555, has died at the age of 78.

Born Swiss, he moved to the USA at the age of 24 to  take an MSEE and MBA. He worked in R&D at PR Mallory and, after six years, decided he wanted to join a company which made ICs rather than researched the technology.  

He went to see all the top linear companies, TI, Westinghouse, Sylvania, Signetics, Motorola, Fairchild and Sprague and chose Signetics.

It was at Signetics where he invented the 555 timer IC. which was first sold in 1972  and is one of the all-time IC best-sellers. It is still in widespread  use today. In 2003 Camenzind estimated that a billion 555s were still being manufactured every year.

It took Camenzind a year to design it, working on a contract after Signetics had fallen on hard times and had laid off half its engineers.

Signetics never patented the 555, believing that once companies started patenting ICs and technologies they would all be at eachothers' throats in the law courts.

Before he designed the 555, Camenzind had resurrected the idea of the phase locked loop which he had come across while reading a back copy of the proceedings of the Instritute of Radio Engineers. He persuaded Signetics to work on the idea and came up with the 565 and the 566.

Those ICs were the basis for the subsequent 555 - a designation suggested by Signetics' marketing manager Art Fury who had a gut feeling that the chip would fly.

Many years later he said: "I wouldn't do it like that again." But no one has improved on it.

Camenzind  started his own company, Interdesign, in 1971 which he sold to Ferranti in 1977.




  1. Yes anonymous, I have used the 7555 CMOS version, and I know it does not suffer from output stage shoot-through when switching.
    Having said that, whenever I can put up with the extra supply current and slightly inferior versatility of the bipolar version, I do – favouring the better robustness to ESD!
    It’s a tribute to Hans that Dave Bingham designed the 7555 with exactly the same pin functionality as the original. Hans just got this right, first time…

  2. Did you ever try the Intersil ICL-7555 C-Mos version (circa 1974)?? There design ( by Dave Bingham ) does not “crowbar” the output stage while switching.

  3. Rest in peace Hans. Pia be strong.

  4. Indeed, george. It was a simpler age when getting stuff to work was all that mattered.

  5. georgegrimes-ti-com.myopenid.com

    What incredibly prophetic words these were:
    Signetics never patented the 555, believing that once companies started patenting ICs and technologies they would all be at eachothers’ throats in the law courts.

  6. Why wouldn’t he do it like that again, I wonder? The only nasty things about the 555 are the gulp of current it draws when switching states, and the fact that the output doesn’t pull up particularly close to the positive supply rail.
    Otherwise, the 555 is a classic! One of my favourite IC’s – almost always the traditional bipolar version.
    RIP Hans Camenzind.

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