retroelectro
development of a microcircuit version of the famous Dolby noise reduction technology for consumer equipment. Two years later, in 1973, Signetics released the NE 545 Dolby noise processing integrated circuit. Interdesign did this from a small office at 165 S Murphy Ave, which he says was between two Chinese restaurants in downtown Sunnyvale, CA. One of the restaurants, Tao Tao Café, is still open if you’re nearby. Soon Interdesign’s success allowed Hans and his team to move the company to an office park on the other side of Sunnyvale. The new building was thirty thousand square feet. Hans and James had learned quite a lot and had started fabricating their own integrated circuits in-house. Back then there were two avenues for circuit board development, have an ASIC built, like Signetics would do, or develop standard off the shelf logic parts, the Monochip was right in the middle, providing an assortment of useful logic gates, comparators, timers, etc. all in a single DIP package. Interdesign designed a variety of these chips for the market. In late 1974, James R. Cunningham, who was the General Manager of
a large test equipment company, resigned from his job to come work as president of Interdesign. His plan was to design a whole line of affordable test equipment, built around the Monochip series of chips. It does not look like this effort got off the ground before the company was being courted by interested parties. “When we assessed the directions the company wanted to go recently, we asked ourselves why should our customers be the only ones to take advantage of this approach, it was obvious that in certain areas, such as instrumentation, we had the key to our future growth.” – J.R. Cunningham concerning using Monochip to develop low-cost and high-margin test equipment. The Monochip line made Interdesign a big name in the industry and, in 1977, he sold Interdesign to the British company Ferranti. Ferranti would continue
triggered and produce a single cycle only.’ Nothing like this had been put to market yet. It could reduce space and cost to produce a study clock signal, but some people were opposed to this concept. His proposal was met with protests that it was a wasted effort and would shoot Signetics in the foot because it would hurt op-amp sales and op-amps were their biggest seller. It took the linear IC marketing manager, Art Fury, to champion the device, which Art would later name the ‘NE555 Timer’.
Interdesign, James Victor Ball [6]. James, himself an Austrian immigrant, became Interdesign’s Vice President and Hans’ right hand. Hans and James had both gone to Northeastern University for their master’s degree in electrical engineering and worked at P.R. Mallory, where they met. His contract gave him one year to design and test the 555 timer. With his schedule, he claims the breadboard layout alone took six months of his twelve-month contract. In the end, his final design consisted of twenty-three transistors, fifteen resistors, and two diodes. 1972: the five-five-five was the beginning The 555 timer was first introduced in the Signetics 1972 Full Line Catalog [8]. Being very industrious, he also released his second textbook during this time, ‘Electronic Integrated Systems
Figure 3: Electronic Design 21
Figure 5: Electronics - James Cunningham
Design’ in 1972.
studying for an M.B.A. and teaching electrical engineering classes in the mornings. Not long after, however, Signetics came back, asking him to return. He declined, instead requesting an independent contractor position. The NE555 Timer would be Interdesign Inc.’s very first freelance contract. Soon Hans would find himself in the same conference room he was in when he worked for Signetics, with the same engineers he worked with. He was here to propose a new design. This new design would be both an oscillator and a timer. In his book, ‘Designing Analog Chips,’ he says he described it to Signetics as ‘an oscillator whose frequency could be set by an external resistor and a capacitor and was not affected by changes in either supply voltage or temperature… modified so it could also be
Interdesign also developed a new concept called ‘analog/linear master slice’, which was built into a complete family of integrated circuits named ‘Monochip’. The Monochip-A was released in late 1971 and made it more accessible for designers to develop ‘ASIC’ type of designs with off the shelf parts for less money and less time. During this time, Interdesign also became the centerpiece in a partnership between Signetics and the UK’s Dolby Laboratories. According to the October 1971 Issue of Popular Electronics, Interdesign would ‘consult’ on the
“The reaction of the Signetics engineering group was disappointing. A user can make a timer from a comparator, a flip-flop, and a zener diode, they said; there is no need for another IC. Had it not been for Art Fury, the marketing manager for linear ICs, the project would have died before it started. Art simply had the gut feel that
such a circuit would be useful. But even he was surprised by the outcome.” – Hans Camenzind
With this new contract, Hans started his own company,
Fun fact: the office that Hans Camenzind designed the 555 timer in is now a real estate broker’s office
Interdesign. Soon after, Hans brought a friend he met in Massachusetts into
Figure 4: Announcement of Interdesign developing what became the Signetics NE545 Dolby Noise Processor” Citation: Popular Electronics - Oct 1971 Page 90
Figure 6: MonoChip-A Dies
we get technical
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