Candidate generation for 45 degree routing for mixed-signal layout

This paper presents an efficient methodology for automatic 45-degree and 90-degree routing of mixed-signal layouts. Non-Manhattan geometries in routing have the advantage of lowering the bound on the shortest route between terminals as well as lowering the via count through use of metal bends. These non-Manhattan routed designs can be employed to reduce interconnection length, signal delay, circuit area, and power consumption over 90-degree routing. When combined with our previous and ongoing work in routing digital and analog circuits, the routing technique presented here will provide an improved mixed-signal routing environment. The algorithm described in this paper generates candidate routes with 45 and 135-degree segments for any two terminal net. Each candidate is guaranteed to be shorter or as short as the Manhattan distance between the terminals.