Shumbler: a 155 Mb/s BiCMOS synchronous multiplexer chip for abroad-band customer premises network

The shumbler (shuffler/scrambler) is a circuit designed and fabricated to form part of a broadband customer premises network. The circuit is implemented in 1.2-μm BiCMOS double-metal technology. The circuit is bidirectional, and can perform the functions of scrambling and shuffling or descrambling and unshuffling by means of control signals to three integrated multiplexers. The shumbler also includes a programmable multiplexer that allows the selection of one out of the 16 output channels of the shuffler through a serial output for local system test purposes. The shumbler circuit interfaces emitter-coupled-logic (ECL) and transistor-transistor-logic (TTL) logic levels using a single power supply of -5 V, dissipating 1.5 W, and encapsulated in a 68-pin LCC package with a flat heat spreader which ensures a thermal resistivity of about 10°C/W