Analog: Back to the future, part two

-July 16, 2012

Part one of this series covered op amp history from National Semiconductor. This second part of the series covers Philbrick Nexus, Burr-Brown, Analog Devices and Linear Technology history and contributions in op amp history up to the 21st century offerings from these companies

Philbrick Nexus

Figure 1: George Arthur Philbrick, Founder of GAP/R George A Philbrick Researches

Philbrick Nexus was the company that launched the commercial use of the Operational Amplifier in 1952.

The first commercial Operational amplifier was the K2-W op-amp. It was based on the amplifier used in the Philbrick K3 modular Analog-Computer "black boxes ". 

That amplifier's basic circuit architecture, in turn, was probably inspired by an earlier amplifier designed by Loebe Julie   The K2-W Operational Amplifier entered the commercial market in 1952, and was last manufactured in 1971. It performed mathematical Operations in analog computers. Soon after, the K2-W and its successors saw wide application in industry. See Figure 2. The Analog Computer was the educational vehicle to familiarize the engineer and the engineering student, with Operational Amplifier techniques.


Figure 2: The K2-W direct-current operational amplifier “for use in electronic computers” circa 1947 (From the Proceedings of the I.R.E. in a paper entitled “Analysis of problems in dynamics by electronic circuits” by J.R. Ragazzini, R.H. Randall, and F.A. Russell)

Editor’s note: John R. Ragazzini was dean of the School of Engineering and Science at New York University in the Bronx when I went there from 1968 to 1972---great guy and brilliant engineer.

Burr-Brown (BB) Op-Amp History Review

The term “Op-Amp” was first coined around 1947, but the concept of a DC coupled feedback amplifier was understood in the 1920s.  The need for analog computers during World War II brought the op-amp into wide use.  Of course, these amplifiers were all made with vacuum tubes.

It was not until 1956 when Burr-Brown introduced the first commercial transistorized amplifiers and it was 1958 when they introduced the model 130, the world’s first transistorized op-amp.

Looking at the big picture, one clear evolutionary path was from “boxes” to sub-micron integrated circuits with “no” packages (chip-scale). 

Figure 3: The big picture of the evolution of the Burr-Brown op amp (Courtesy of Howard Skolnik, one of the great analog designers at Burr-Brown in the early days)

1956    BB started with “instruments” in wooden boxes.  The 1st product was the model 100 AC Decade Amplifier (See Figure 4).  This was not an op-amp.  Other early products, in wooden boxes, included a Differential AC Amp, Square Wave generator, Variable Gain Preamp and AC Millivolt Meter.

Figure 4: The Model 100 was the first product that Burr-Brown made in 1956

1957    Tom Brown visited several major customers including MIT to see how they were using BB products.  To his surprise he found that they were removing the circuits and discarding his beloved boxes!  He learned two important lessons:  Smaller is better and making “components” is better business than making “end products.”

The model 130, the world’s 1st transistorized op-amp was introduced.  This was a completely discrete design using just 8 transistors on a PC-board in a 3 ½” long aluminum shell.

The desire for “smaller” led BB to the potted module concept.  While still using PCBs and all discrete components, innovative techniques greatly increased density.  The 1501 was the first modular op-amp and is now part of the Smithsonian collection.

The 1st monolithic (IC) op-amp was introduced by Fairchild (uA702 Bob Widlar). It was not very useful and was later superseded by the uA709 (1965).

1965   The 1538 module was the 1st transistorized chopper stabilized op-amp.
The 1552 module was the 1st FET-input op-amp.
           The 1553 module was the 1st transistorized chopper stabilized op-amp. MOSFET-input op-amp.

1966   The 3051 was BB’s 1st monolithic op-amp (Jerry Graeme on outside Fab).

The uA741 was introduced by Fairchild (Dave Fullagar).

The move to hybrids was well underway. The ability to mix and match chip-level along with discrete components on a thick-film substrate opened the door to complex circuits with very high performance.

  Trimming of thick-film resistors allows higher precision in both modular & hybrid designs.
  1st monolithic op-amp produced on BB Fab (3051).

  Trimming of thin-film resistors provides improved stability and smaller size in hybrids.

1st two-chip hybrid op-amp (OPA102) combined a bipolar monolithic chip with a dual FET chip to produce high performance at lower cost than before.

Monolithic dielectric isolation (DI) process available to BB designers greatly increasing their capabilities.

INA101 is BB’s 1st monolithic instrumentation amplifier.

OPA100 ultra-low bias current op-amp is 1st produced using the BB DiFET (DI BiFET) process.

OPA111 Low noise, low drift op-amp built on BB DiFET process.

1986   INA110 is BB’s 1st monolithic BiFET instrumentation amplifier.

OPA445  Hi-Voltage BiFET op-amp. +/-45V.

OPA627 Near “ideal” op-amp built on BB DiFET process.  250uV Vos, 5pA Ibias, 5nv Noise, 16MHz BW, 55V/us SR, +/-18V supplies.

1996   OPA237    1st op-amp in SOT-23 package.
           OPA2237 1st dual op-amp in MSOP-8 package.

           OPA336  1st BB op-amp on 0.6u CMOS.

           OPA2652 1st op-amp on BB’s CBC-10 process.

Comparing the first transistorized op-amp to a modern chip-scale device. 

Table 1: A Comparison of the first transistorized op-amp to a modern chip-scale device.

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