NIM Fast Logic Modules Utilizing MECL III Integrated Circuits

The design and construction of fast logic modules for nuclear instrumentation has always been a costly and time consuming effort. The demands for and on modules have increased considerably; greater quantities with improved performance capabilities are needed. Improved performance and reduced module cost are obtained by using commercially available emitter-coupled logic and a minimal amount of interface circuitry to form compatible functional circuits which can then be combined to create the various modules necessary for nuclear instrumentation. This paper describes the operation of several functional circuits that have been designed at the Lawrence Berkeley Laboratory to effectively utilize the Motorola MECL III line of integrated logic circuits in NIM Standard fast logic modules. The modules process pulses with rise and fall times of approximately 1 ns and can operate at pulse repetition rates in excess of 300 MHz, yet their cost is less than half that of commercially available 200 MHz units.