Open AccessPassive switched‐capacitor filter with complex poles for high‐speed applications
Author(s) -
Payandehnia P.,
Maghami H.,
Kareppagoudr M.,
Temes G.C.
Publication year - 2016
Publication title -
electronics letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.375
H-Index - 146
ISSN - 1350-911X
DOI - 10.1049/el.2016.2487
Subject(s) - voltage controlled filter , low pass filter , high pass filter , m derived filter , active filter , band stop filter , filter (signal processing) , filter design , butterworth filter , electronic engineering , switched capacitor , prototype filter , constant k filter , bandwidth (computing) , electronic filter topology , band pass filter , all pass filter , center frequency , control theory (sociology) , engineering , capacitor , computer science , electrical engineering , telecommunications , control (management) , artificial intelligence , voltage
A novel complex‐pole switched‐capacitor lowpass filter topology is presented. The proposed scheme features sharper roll‐off in the frequency response and reduced in‐band loss compared with a real‐pole filter. It provides higher stop‐band rejection for the same bandwidth. Hence, the required filter order and chip area are reduced. These improvements are achieved without adding more active blocks to the real‐pole filter, and with minimal added complexity. The proposed filter has the same low‐output thermal noise level as the real‐pole filter. These features, combined with a wide‐frequency tuning range, make the filter suitable for high‐speed, low‐noise, and low‐power applications. A fourth‐order 200 MS/s filter prototype was designed in 0.18 µm Asahi Kasei Microdevices Corporation CMOS technology. Simulations verify that the average in‐band loss is reduced by 3.2 dB compared with the real‐pole filter. The 3 dB cut‐off frequency can be tuned from 470 kHz to 17.5 MHz with 100 dB maximum stop‐band rejection.