Op-amp based CMOS field-programmable analogue array

The field-programmable analogue array (FPAA) is crucial to improving turnaround time for analogue circuit designs. The critical parameters when specifying the design are bandwidth and accuracy. FPAAs reported to date compromise one parameter when optimising the other. A new continuous-time FPAA architecture is presented which simultaneously achieves bandwidth and repeatability comparable to the accuracy tolerance of switched-capacitor FPAAs and the bandwidth of continuous-time FPAAs. It uses continuous-time operation for high bandwidth and introduces buffered CMOS pass-switches and ratioed function blocks to overcome accuracy limitations. A prototype circuit is presented and applied to op-amp based circuits. The results show that the new FPAA offers the best combination of bandwidth and accuracy published to date