Transistor Museum Early Silicon Power Transistor History by Joe Knight Pacific Semiconductors Inc

A SURVEY OF EARLY POWER TRANSISTORS

by Joe A. Knight

PACIFIC SEMICONDUCTORS INC 1960s SILICON

POWER TRANSISTORS

As is common to all high power devices, be they tubes or semiconductors, the use of complementary drivers is essential to achieving their full output potential. Thus, in 1960, PSI also released a series of smaller Triple-Diffused Silicon Mesa power devices called the 'PT530' series. These were rated at 12-watts of dissipation up to 70 Mhz and were fully capable of driving the 'PT900' series Power Transistors to their rated output.

ABOVE, L-to-R: The first item is a "PT530" type with a power output of 3 watts at 70 Mhz (these devices are about the size of a dime in diameter). The middle cut-open device shows the relatively small silicon junction element made possible with the new 'mesa' type fabrication. The last item is another silicon mesa output variation, the "PT531".

Alas, PSI never did seem to gather the momentum the company started out with in their new high-power silicon output devices, likely as their primary business focus at that time was in the realm of diodes and rectifiers. In 1964 PSI was re-incorporated into the then parent company TRW as the new "Semiconductor Division" where they continued for many years making leading-edge IC's and uhf/ RF power devices widely used in the space and military defense programs.

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Joe A. Knight Early Power Transistor History – PACIFIC SEMICONDUCTORS INC Page 4