An 8 MHz, 80 Ms/s switched-current filter

Since its introduction in 1989, the switched-current (SI) technique for sampled-data signal processing has claimed the advantage over switched-capacitors of needing only digital CMOS processing, making it cheaper and more amenable to mixed-signal ICs. Attempts to raise the performance to match that of switched-capacitors has had mixed success, and some silicon implementations have been reported. A recent advance, called S/sup 2/I, promises the highest overall performance yet. This paper demonstrates that switched current filters can not only compete with switched-capacitors and use simpler IC processing but also perform well with sampling frequencies of at least 80 MHz. >