Open AccessCMOS‐based high‐order LP and BP filters using biquad functions
Author(s) -
Prommee Pipat,
Saising Ekkapong
Publication year - 2018
Publication title -
iet circuits, devices and systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.251
H-Index - 49
eISSN - 1751-8598
pISSN - 1751-858X
DOI - 10.1049/iet-cds.2017.0493
Subject(s) - digital biquad filter , chebyshev filter , cmos , electronic engineering , analogue filter , band pass filter , low pass filter , rlc circuit , electronic circuit , frequency response , computer science , filter (signal processing) , voltage , mathematics , engineering , electrical engineering , capacitor , digital filter
This study proposes the complementary metal–oxide–semiconductor (CMOS)‐based current‐modehigh‐order active low‐pass (LP) and band‐pass (BP) filters using biquadfunctions. The passive RLC Chebyshev ladder filters were used as the prototype,and the mesh‐ and nodal‐analysis methods to derive the biquad functions. TheCMOS‐based transistor‐level biquad circuits were subsequently realised from thebiquad functions. The high‐order active LP and BP ladder filters were thensynthesised from an amalgamation of the biquad circuits. Simulations werecarried out to verify the performance and functionality of the LP and BP ladderfilters. The results revealed that the proposed ladder filters were operable inthe high‐frequency range and electronically tunable, given a low‐voltage supplyof 1 V for the entire circuit. The proposed filters could also achieve the LPfrequency response of 300 kHz–30 MHz and BP centre frequency of 200 kHz−20 MHzby means of the bias current ( I B ) manipulation from1 to 100 µA. Moreover, the multi‐tone simulations were undertaken to assess thefiltering performance of the proposed filters and the results are agreeable withthe design specifications.