MATLAB®/Simulink® Models of Mixed-Signal Circuits to VHDL-AMS

Nowadays, due to the increasing complexity of circuits and systems incorporating mixedsignal components, many designers recognise the advantages of, and in some cases the necessity for, mixed-signal modelling and simulation of the circuits and systems as a whole prior to, during and post production of the circuit or system. This is particularly so within the microelectronics (semiconductor) arena. This, coupled with the emergence of a range of description languages that find use in the modelling and analysis via simulation of microelectronic circuit designs, means the ability now exists to design complex signal processing functions in both the digital and analogue domains. Modelling and simulation has increased the designer efficiency and ability to develop increasingly complex and useful electronic circuits, particularly at the integrated circuit (IC) level. Each type of circuit considered has its own particular requirements in terms of design performance (specifications), design methodologies required to realise a design, modelling and simulation toolsets utilised, designer experience and skills set. This chapter will consider design aspects relating specifically to data converters, in particular the digital-to-analogue converter (DAC). In many electronic systems, the data converter (both the analogue-to-digital [A/D] and digital-to-analogue [D/A] converter) provides an important electronic function. The developed converter design will be provided to the end-user as either a discrete integrated circuit or as a macro cell within a larger design, see Fig. 1. The data converter provides the primary interface block between the analogue ‘real’ world and the digital signal processing circuitry typically found in many control, instrumentation and, generically, ’mechatronic’ systems. The converter design performance is continually increasing to meet the changing needs of the end-user applications, in particular: an increase in resolution (number of bits); an increase in speed of operation driven primarily by the communications applications; the operation of the circuit on lower power supply voltages and with lower power consumption driven primarily by the need for portable electronic circuit applications.