Canonic adaptor realisations for wave switched-capacitor filters

The principles of the design of canonic wave SC adaptors based on parasitic-insensitive voltage storage and subtraction are described. The adaptors may be used in any filter configuration and have a minimum number of operational amplifiers.     

Adaptor realisations for wave switched-capacitor filters with reduced capacitance spread

The design of wave SC adaptors with very low capacitance spread is described and illustrated for the case of the unit-element cascade filter. The adaptors are canonic in the number of operational amplifiers and are parasitic-insensitive.     

Minimal realisations of a class ofoperational-mirrored-amplifier-based floating impedances

Four operational mirrored amplifier (OMA)-based floating impedance configurations are presented which require only a minimum number of (three) OMAs as against four OMAs in the previously published circuits while preserving all other advantageous features of the earlier structures     

New tunable synthetic floating inductors

Three new active RC synthetic floating inductance circuits are proposed which realise lossless f.i. and series and parallel RL impedance, respectively employing three and two second-generation current conveyors as active elements. The novel features of the new circuits are that (i) in contrast to available operational-amplifier circuits for f.i.s, the circuits presented here do not require component matching for the desired realisation; (ii) the new circuits employ a minimum possible number of passive elements (only two resistors and a capacitor); (ii) in all the new circuits, the inductance value is independently controllable through a single resistance.     

Nonreciprocal representation of the floating inductor with grounded-amplifier realisations

The floating inductor is approximated to by the nonreciprocal transmission matrix (1, Ls; 1/R, 1), where L = CR2 with R sufficiently large and CR2 constant. Representations of this matrix are obtained by a form of synthesis procedure and are realised with only one type of grounded operational amplifier. Results are given which show their performance in a lowpass filter.     

Generation of new two-amplifier synthetic floating inductors

Although many lossless floating inductance (LFI) circuits employing three or four operational amplifiers are known in the literature, The and Yanagisawa's paper appears to be the first as well as the only work where an LFI realisation with only two operational amplifiers has been achieved. The present letter outlines a procedure by which a number of new two-amplifier LFI configurations are derivable.     

Switched-capacitor simulation of floating inductors using gyrators

A simulation of a floating inductor using two switched-capacitor gyrators in cascade is presented.     

A simple method for producing floating inductors

A simple method for producing ungrounded inductors using a gyrator is described. Floating inductors may be obtained from either grounded or ungrounded capacitors. The technique has an advantage in the low number of amplifiers required.     

Characterization of spiral inductors with patterned floating structures

The impact of two different types of floating patterns on spiral inductors was investigated. Both patterned trench isolation with a floating p/n junction and floating metal poles were implemented underneath reference spiral inductors. All three types of inductors have an identical spiral geometry. Combination of patterned trench isolation with a floating p/n junction increases maximum quality factor (Q/sub max/) by 17% compared to the reference inductors. The floating metal poles enable adjustment of the frequency at Q/sub max/ (f/sub max/) without hampering the Q/sub max/. A ladder-type lump-element model was employed to analyze inductor performance after it was demonstrated to precisely capture behavior of all three inductors. Enhancement of the quality factor due to patterned trench isolation with a floating p/n junction was found to result from an increment of effective resistivity in substrates. Reduction of the frequency f/sub max/ due to the floating metal poles was caused by increasing effective coupling capacitance between the spiral inductors and substrate.     

Alternative approach to the design of switched-capacitor filters

An alternative switched-capacitor filter design is shown to be possible using an economic form of c.c.d. A simple example of a biquadratic digital-filter section is included to illustrate the point. This leads to comment on the relationship between switched-capacitor filters, the N-path filter and the digital filter.     

A simple method for producing floating semiconductor inductors

A simple method for simulating floating inductances in integrated circuits is described in this correspondence. The principle of simulating inductance is the impedance conversion. Since the characteristics of this simulated inductance are independent of the active parameters of transistors, excellent temperature characteristics and high reproducibility are obtained.     

Novel floating simulated inductors with wider operating-frequency ranges

In this paper, a number of simulated floating inductors (FIs) employing second-generation current conveyor (CCII), current-feedback operational amplifier (CFOA), differential voltage current conveyor (DVCC) and differential difference current conveyor (DDCC) are proposed. They employ only a grounded capacitor; accordingly, they are suitable for integrated circuit (IC) implementation. Some of the developed FI simulators demonstrate the feature of improved low-frequency performance while the other ones suffer from the Z/Y terminal parasitic resistors bringing extra series resistors to the inductances of the simulated FIs. Two novel methods for reducing/eliminating the unwanted series resistance in equivalent inductances of the FIs are developed, one of which is called the direct design technique accomplished by adjusting the resistive component/components of the FIs. The series resistors of the FIs affecting their low-frequency performance can be canceled by adding floating negative resistors in series, which is another method. Three of the presented FIs as examples are chosen in order to verify the developed method, perform their simulations and show their performance.     

Switched-capacitor simulation of floating inductors using the operational amplifier pole

An active switched-capacitor realization of a floating inductor using the operational amplifier pole is described. The circuit uses two operational amplifiers, two capacitors, and two toggle switches.     

New canonic active RC realizations of grounded and floating inductors

Two new canonic active RC networks are proposed for the simulation of grounded and floating lossy inductors. A grounded inductor is simulated with one operational amplifier, four resistors and one grounded capacitor. The circuit for a floating inductor employs two amplifiers, six resistors, and only one capacitor.     

Readily biased wideband gyrator circuit for floating or earthed inductors

A transistor-circuit realisation for a wideband gyrator circuit, the biasing of which does not rely on any matching between p-n-p and n-p-n transistors, is described. A unique feature that distinguishes this biasing method from other known methods is that it is fully integrable, since it needs no adjustable components for bias adjustment.     

New approach to the design of active floating inductors in MMICtechnology

An original method for the determination of all possible inductive circuits as a function of the number of field-effect transistors (FETs) used is described in this paper. The method is of general use in monolithic microwave integrated circuits. Circuits with large inductance, either positive or negative in value, can be obtained along with low loss or even negative resistance     

LC-VCOs using spiral inductors with single- and dual-layer patterned floating shields: a comparative study

This letter studies and compares class-B VCOs using spiral inductors with the proposed dual-layer patterned floating shield (DL-PFS) and conventional single-layer patterned floating shield (SL-PFS). The proposed DL-PFS technique utilizes two lowest metal layers to effectively reduce the capacitive induced current to the substrate in an on-chip spiral inductor, thereby boosts its Q-factor by 40% when compared with the conventional SL-PFS approach. We fabricated, as a proof of concept, the class-B LC-VCOs using the DL-PFS and SL-PFS in 0.13 µm CMOS. Operating at 10 GHz, the VCO with the DL-PFS inductor measures a 3.6 dB phase noise (PN) improvement at the same power consumption of 2.12 mW. Specifically, the VCO with DL-PFS inductor is tunable from 9.3-to-10.1 GHz and measured PN at 10 GHz is ?132.5 dBc/Hz at 10 MHz offset while consuming 2.12 mW at the lowest 0.6 V supply. The achieved figure-of-merit (187.4 dBc/Hz@1 MHz offset) compares favorably with the recent state-of-the-art.     

Circuit realisations of conjunctors and traditors

Circuit realisations of conjunctors and traditors are presented. In particular, a conjunctor is shown to be realisable by a resistive nonlinear network made up of four nonlinear resistances and seven linear controlled sources. Similarly, a traditor is shown to be realisable by a dynamic nonlinear network made up of two linear capacitances, eight nonlinear resistances and 16 linear controlled sources.     

MOS switched-capacitor filters

In the past several years, much progress has been made in bringing the economies of integrated-circuit technology to bear on the realization of voiceband frequency selective filters. This paper will review one approach to this problem, the use of switched-capacitor techniques. The paper emphasizes the practical aspects of switched-capacitor filter design under the constraints imposed by MOS integrated-circuit technology. The basic operation of switched-capacitor filters is reviewed, followed by a discussion of the properties of the various circuit building blocks in MOS technology. Finally, a summary of several filter organizations which appear to be well suited to switched-capacitor implementation is presented.