Analogue and mixed-signal IC design

Recent developments in fabrication technology have led to the advent of double-poly CMOS processes, which are attractive for analogue ICs. The process allows high-value capacitors to be made using the two polysilicon layers as the conducting plates, thus using a much smaller area than that required by earlier metal-poly capacitors. The BiCMOS process is particularly relevant to making mixed analogue/digital devices; it blends N- and P-channel complementary MOS devices with NPN bipolar devices in the same process, giving the ability to produce CMOS and bipolar transistors on a single chip. This means that high-performance analogue circuits can be mixed with high-density, low-power digital circuits, offering a single-package mixed-signal system. The authors highlight the rapid growth in the mixed-signal ASIC market. They examine the crucial developments taking place in analogue CAD environments, and in the device technologies on which the growth critically depends