Analogue-digital ASICs

The inexorable increase in levels of integration of electronic circuits has most often been exploited using digital signals. So much so that design engineers have sought to digitise analogue signals as early as possible in the signal processing chain, and performed digital processing wherever practicable. However it is increasingly being accepted that such an approach is not appropriate for many applications, and that circuits which combine analogue and digital signals can provide superior solutions. There are at least three factors which support this trend. Firstly improved process technology giving better dimensional and parametric control and the availability of BiCMOS and CMOS processes able to support both analogue and digital components. Secondly the maturing of discrete time circuit techniques giving competitive high performance solutions. Thirdly the gain in terms of reliability and reduction in cost achieved by mixing analogue and digital signal processing and hence implementing 'systems' on a single substrate. It is therefore timely that wide ranging books such as this one, on the subject of mixed analogue digital ASICs should appear. It comprises eighteen chapters contributed by leading academics and practising engineers in industry. The chapters are arranged in four sections: Processing technology; Circuit Techniques and Building Blocks; Design and Applications; and CAD and Supporting Tools.