M.H.L. Kouwenhoven

Nonlinear analysis of noise in static and dynamic translinear circuits

For translinear filters, or log-domain filters, calculation of the maximal signal-to-noise-ratio, an important filter specification, is not trivial, due to the inherent companding behavior and the nonstationary nature of the transistor noise sources. To address this issue, a nonlinear noise analysis method is proposed. Based on large-signal calculations, expressions for the first-order noise and signal-noise intermodulation terms are computed. The procedure is generally applicable both to static and dynamic translinear circuits, as illustrated by a number of generic examples.

Design of High Dynamic Range Fully Integratable Translinear Filters

This paper addresses the non-linear noise and dynamic-range properties of bipolar and MOS (both in weak and in strong inversion) translinear integrators, following a systematic top-down approach. Several design principles to achieve an optimal dynamic range are derived. A qualitative comparison of a bipolar or weak-inversion class-AB translinear integrator and the well-known linear gm − C integrator reveals that the former is an interesting candidate, especially for low-voltage and/or low-power operation. As an example, a ±1.65-V bipolar translinear integrator is presented that makes dynamic-range optimization possible by adjusting just one bias current. Its application in an audio filter yields a 63-dB dynamic range and a virtual dynamic range of 76 dB, while the current consumption can be as low as 310 nA.

The Effect of Mismatches and Delay on the Quadrature Error of a Cross-Coupled Relaxation Oscillator

Cross-coupled relaxation oscillators can produce two highly accurate quadrature output signals (Verhoeven, 1992). We present a high-level model of these oscillators in terms of circuit parameters, from which we obtain explicit equations for duty-cycle, oscillation frequency, and quadrature error. They show the influence on the oscillator performance of component mismatches and other nonideal effects, such as delays. The results provide useful guidelines for the design of high performance oscillators. The theoretical results are confirmed by simulation and by measurements on a test chip.

The effect of mismatch and disturbances on the quadrature relation of a cross-coupled relaxation oscillator

Cross-coupled relaxation oscillators are capable of producing two stable and highly accurate, quadrature output signals. We present a complete high-level model of the cross-coupled relaxation oscillator in terms of circuit parameters, from which we obtain explicit expressions for duty-cycle, oscillation frequency and output phase relation. They predict the influence of mismatches and other disturbances such as delays, at circuit level. The results provide useful guidelines for the design of a high performance circuit of such an oscillator. The theoretical results are confirmed by simulation and by experiment.

Analysis of noise in translinear filters

To describe the effects of noise in translinear filters, large-signal equations have to be used, due to the internal non-linearities and the nonstationary nature of the noise sources. In this paper, a noise analysis method is proposed, which takes into account the non-linear and non-stationary aspects. As an example, the signal/spl times/noise intermodulation is calculated for a class A and a class AB operated log-domain filter.

HF low noise amplifiers with integrated transformer feedback

This paper proposes the concept of an adaptive, wideband LNA, based on double-loop negative feedback with an integrated HF transformer, resulting in an inherent matched input impedance. It offers the possibility to design and bias the input transistor for minimum noise and has the potential to increase linearity, without affecting the input impedance.

The influence of non-linear distortion on OFDM bit error rate

The influence of bandpass non-linear distortion on an OFDM signal is investigated. The spectrum of the distorted signal and the resulting detection errors are determined. Non-linear distortion of OFDM signals can significantly increase the receiver BER. Previous analyses rely on simulation, or apply to specific non-linearities only. Here, an analysis is presented which is applicable to any weakly non-linear distortion of an OFDM signal. Simple analytical expressions are derived which allow a designer to choose parameters without performing simulations. Further, it is shown that the error on each OFDM subcarrier is approximately equally large.

Noise considerations for translinear filters

Translinear filters exhibit unconventional noise characteristics, due to the internal nonlinear behavior. In this paper, the maximal signal-to-noise-ratio and the dynamic range properties of translinear filters are discussed, and the relation between these two specifications and the inherent instantaneous companding is described.

Dynamic translinear circuits

A promising new approach to shorten the design trajectory of analog integrated circuits without giving up functionality is formed by the class of dynamic translinear circuits. This paper presents a structured design method for this young, yet rapidly developing, circuit paradigm. As a design example, a 1-V 1.6-μA class-AB translinear sinh integrator for audio filter applications, is presented.

A quadrature relaxation oscillator-mixer in CMOS

This paper describes the design of a quadrature cross-coupled oscillator circuit integrated which also realizes the mixer function in a phase lock loop (PLL). This should be able to provide a very accurate phase relation (<1/spl deg/). This combined oscillator/mixer is first evaluated using a high-level model, in up and downconverter configurations. A circuit implementation is then carried out, in which all the variables are kept independent at circuit level, ensuring a practical implementation close to that of the high-level model. The circuit is designed in a standard 0.35 /spl mu/m CMOS technology with an oscillation frequency of 900 MHz, it has an overall area of 521 /spl times/ 515 /spl mu/m/sup 2/ (157 /spl times/ 119 /spl mu/m/sup 2/ for the IQ oscillator/mixer circuit) and a power consumption of 70 mW with a 3 V power supply. The circuit performance is evaluated by simulation.