Best usage of free-space capacitors in ASIC regulators

[摘要] In this work we examine how to improve the performance of voltage regulatorsin application specific integrated circuits (ASICs) by placing capacitorsinto free layout space. The problem arising after layout, when there areareas not covered by functional elements, is where to connect the free-spacecapacitors (FSCs), as they can be connected to the input or the output net ofa voltage regulator. Therefore we designed a testbench for mathematicalcalculations and one for simulations to identify the influence of acapacitance connected at these certain positions. We mainly focused on PSRanalysis while not losing sight of transient effects. The results ofcalculation and simulation illustrate that the best solution is to split thecapacitance half by half to both possible nets if no output capacitance wasinstalled during design. Otherwise a ratio of one to one for input capacitance tooutput capacitance has to be set up for best performance.

[学科分类] 电子、光学、磁材料