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
  • Istanbul Technical University Affiliated: Yes


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.