ASIC-a case study

Presents an example of ASIC being used to provide the classic example of reduction in cost, power dissipation and component count, on a product using CMOS and bipolar technology semi-custom design. The product concerned is a 3.5 inch Winchester disk drive with an ST 506 interface. Prior to the LSI integration program the electronics assembly was contained on a double sided, six layered printed circuit board. By integrating with semi-custom devices it was possible to reduce the component count from 400 to 200 devices, utilise a four layer PCB and reduce the power dissipation. Different phases of the LSI program are described from the initial feasibility study to the high volume production for one of the devices known as the servo demodulator chip (SDC)