TitleMicrologic evaluation kit
ManufacturerFairchild Semiconductor Corporation
Dimensionsoverall: 2 3/4 in x 9 1/2 in x 13 1/2 in
DescriptionThe object is a set of hardware and descriptive material designed to conveniently enable the user to evaluate the performance of Fairchild's first family of integrated circuits in operating digital subsystems. The hardware includes two printed circuit boards, one containing a counter with matrix and the other a recirculating shift register, sufficient Micrologic ICs (original kit held 28 but 25 remain) to assemble either circuit, two printed "breadboard" circuits together with resistors, capacitors, and connectors.
Fairchild made the Evaluation Kit available (c 1962) to enable computer engineers to have hands-on experience with the set of five new devices called MicroLogic.
Unlike existing logic circuits, the structure of the new integrated circuits permitted testing at only the input and output terminals of the circuit; the internal nodes were not accessible. Computer design engineers at the time relied on being able to know the value and its tolerance of every component in each circuit and to be able to “probe” with meter or oscilloscope the internal nodes of the circuit to verify its design and its operation under varying conditions such as ambient temperature, noise, supply voltage, and clock speed.
These engineers had severe doubts about the usability and reliability of circuits for which only the inputs and outputs could be measured while the internal components and behavior were unknown. They did not trust a transistor manufacturer to design and build logic circuits which would work reliably when connected in logic networks.
To help computer engineers overcome their disbelief, the Applications Engineer wrote “Application Notes” on the testing of MicroLogic elements and designed the “MicroLogic Evaluation Kit,” which enabled the user to use MicroLogic to build examples of two typical computer functions, a counter and a shift register, and to evaluate for oneself their performance in operation.
Another purpose of the Kit was to demonstrate that Fairchild engineers were aware of the issues facing computer logic designers and had incorporated features to aid design and improve reliability. The pin assignments aided layout: input pins on the left side of each element, outputs on the right, supply voltage at the top and ground at the bottom (this helped the computer designer while making life more difficult for the IC designer); a protrusion on the underside of the header held the header spaced above the board to reduce the possibility of solder bridges. Drive capabilities (fan-out) were guaranteed. All devices were shock, vibration, and temperature-tested to military standards. Adhesive decals, one for each member of the uL family, were designed to help in making schematics and layouts. The Keuffe and Esser Company provided mylar sheets with preprinted (in non-photo blue) element pin circles to aid in making circuit board artwork with black tape. The first MicroLogic elements were color-coded; the color on the top of the TO-5-type can indicated the element type. Templates could be used to check the location and orientation of elements on a completed PC board.