MOS-Only Allpass Filters Modified for Low Operating Frequency Range

Yildiz H. A. , Toker A. , Elwakil A. S. , Ozoguz S.

8th International Conference on Electrical and Electronics Engineering (ELECO), Bursa, Turkey, 28 - 30 November 2013, pp.36-39 identifier identifier

  • Publication Type: Conference Paper / Full Text
  • City: Bursa
  • Country: Turkey
  • Page Numbers: pp.36-39


The objective of this paper is to present a modification technique that can be used to alleviate the low-frequency limitations of MOS-only filters. The technique is based on adding an additional pair of cross-coupled transistors to modify the time constant of the filter. In this case, lower frequency operations is attainable without having to use large transistors with higher intrinsic capacitors; hence the chip area occupied by the circuit is kept low. Two existing MOS-only filter circuits are modified to illustrate the versatility of the idea and Spectre simulation results are provided in order to show the proper operation of the circuits.