Design of Programmable Wideband Low Pass Filter with Continuous-Time/Discrete-Time Hybrid Architecture

Yohei MORISHITA
Koichi MIZUNO
Junji SATO
Koji TAKINAMI
Kazuaki TAKAHASHI

Publication
IEICE TRANSACTIONS on Electronics   Vol.E100-C    No.10    pp.858-865
Publication Date: 2017/10/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E100.C.858
Type of Manuscript: Special Section PAPER (Special Section on Microwave and Millimeter-Wave Technology)
Category: 
Keyword: 
Continuous Time,  Discrete Time,  low pass filter,  equalizer,  CMOS,  

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Summary: 
This paper presents a programmable wideband low pass filter (LPF) with Continuous-Time (CT)/Discrete-Time (DT) hybrid architecture. Unlike the conventional DT LPF, the proposed LPF eliminates sample & hold circuits, enabling to expand available bandwidth. The transfer function and the influence of the circuit imperfection are derived from CT/DT hybrid analysis. A prototype has been fabricated in 40 nm CMOS process. The proposed LPF achieves 2.5 GHz bandwidth by wideband equalization, which offers capacitance ratio (Cratio) and clock frequency (fCK) programmability. The proposed LPF occupies only 0.048 mm2 of active area.