Sylvania Germanium Transistors

Germanium transistors from 1955. In the early 1950s Sylvania established transistor and diode manufacturing at their tube (valve) facility in Emporium PA. Manufacturing was transferred to the Electronics Divsions in Woburn Mass. In 1957 it was divided into two new organizations, the Semiconductor Division and Special Tube Operations.
Skyworks, one of the current world leaders in RF components for smartphones has its roots in Sylvania, Woburn.

Comments

Post a Comment

Popular posts from this blog

Burr-Brown PCM1702 A Really Interesting Audio DAC From the 90s

Image
Burr-Brown PCM1702-L I've just acquired from eBay a CD player to complement another very old CD player, both with Burr-Brown Digital to Analog converters. The photo shows the inside of the Denon CD-655 from the late 90s, a super low distortion and high signal to noise ratio CD player which uses 2 x PCM1702 DACs from Burr-Brown. The BiCMOS process 20-Bit PCM1702 was a really interesting DAC which was an improved version of the PCM63P. Early R-2R ladder DACs suffered from some noise/glitches at low output levels (and degraded linearity) due to the Most Significant Bit current source turning on at the lowest volume output point. Multi-bit DACs had significantly higher performance than contemporary 1-bit and "MASH" DACs, but had this one flaw. The PCM1702 was effectively two 19-bit DACs in a complementary design which negated the zero cross point issue. They had all the benefits of R-2R ladder DACs and now removed the other issue. Around this time Burr-Brown were al...
Read more

Fairchild Micrologic - The World's First Integrated Circuits

Image
Fairchild Micrologic Devices Fairchild introduced the Micrologic standard logic family in 1961. These were the world's first ICs, based on Jean Hoerni's revolutionary planar process which laid the blueprint for all future integrated circuits. There were eventually 25 standard logic RTL ICs. Products in the family included the 900, a buffer, 901, a 3 gate counter adapter, the 902, a flip-flop, 923, a JK flip flop and the 959, a 4bit latch. Above is a  3-input NOR device from the early 60s (uL903) in a metal can, and a later packaged JK flip flop (uL923) in a lower cost epoxy topped package. During the 1960s, Fairchild became the first semiconductor company to establish a lower cost assembly facility in the Far East (Hong Kong). Decapped uL903 Micrologic Device The 3-input NOR from Fairchild became the basic building block of the Apollo guidance computer, designed by MIT and built by Raytheon. It used 5,000 3-input NOR ICs and was the first major application of ICs. ...
Read more

SACD Passed me by, Until Now (Updated)

Image
Back in the day I knew about DSD (Direct Stream Digital) and SACD (Super Audio CD) but it passed me by. I was still in Burr-Brown when DSD data converter ICs were first being developed by the design team in Japan, and I'm sure I was present when they were being presented at seminars to customers, but at the time I had little or no interest in diving in personally. Burr-Brown invested heavily in designing ICs for the upcoming market demand, but as history tells us, it didn't become mainstream. Certainly not in the US, less so in Europe, but in Japan there was always demand. Philips and Sony originally developed SACD as the high end next generation of CD, and certainly the format was capable of encoding a significantly higher level of audio information on the platform. DSD was a delta-sigma bitstream format that sampled 1-bit at 2.8MHz. Philips Semiconductors (amongst others) developed an SACD processor and Burr-Brown (amongst others) developed DSD Digital to Analog converters. L...
Read more