Approaches to analogue IC synthesis

In order to meet future integration trends where full analogue and digital systems will be incorporated onto a single integrated circuit, automated analogue synthesis tools will be required. The systems surveyed in this paper address this need with differing approach and versatility. The systems considered are: IDAC/ILAC which are products of CSEM in Switzerland, OASYS/ANAGRAM from Carnegie Mellon University and OPASYN developed by the University of California, Berkeley. OASYS and IDAC are capable of synthesising several different analogue functions with moderate specifications while OPASYN is specifically designed for op-amp synthesis where a numerical optimizer is used to achieve more stringent requirements. In all cases the systems accept high level specifications and produce a set of process-specific fabrication masks. In view of the anticipated importance of analogue synthesis tools, considerable research is being undertaken to extend their capability to higher performance analogue circuits. In addition, other factors such as the number of analogue circuit functions that can be synthesised and the circuit design time need to be improved