OTA-C filters with finite zeros

Citation
F. Galvez-durand et al., OTA-C filters with finite zeros, ANALOG IN C, 19(2), 1999, pp. 207-216
Citations number
6
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Eletrical & Eletronics Engineeing
Journal title
ANALOG INTEGRATED CIRCUITS AND SIGNAL PROCESSING
ISSN journal
0925-1030 → ACNP
Volume
19
Issue
2
Year of publication
1999
Pages
207 - 216
Database
ISI
SICI code
0925-1030(199904)19:2<207:OFWFZ>2.0.ZU;2-S
Abstract
In this paper we present a novel technique for OTA-C filter realizations wi th finite zeros based on doubly loaded passive ladder networks. Only ground ed capacitors are needed; all floating capacitors are replaced with active simulations eliminating bottom-plate parasitic capacitors and non-observabl e poles. Bandpass, highpass and bandstop filters are easily obtained from a lowpass OTA-C prototype applying standard frequency transformations that p reserve the active simulation of floating capacitors, i.e. the finite zeros realization. Also, we address the high frequency stability problem of high pass and bandstop OTA-C filters simulating doubly loaded passive ladder net works. These filters usually have floating nodes where the OTA excess-phase acting over the nodal parasitic capacitance can introduce unstable poles a t high frequencies. The stability problem is fairly the same for highpass a nd bandstop OTA-C filters based on approximations with and without finite z eros; only the most complex case (filters with finite zeros) will be addres sed here.