Leonid Belostotski

Noise figure optimization of inductively degenerated CMOS LNAs with integrated gate inductors

This paper discusses noise figure optimization techniques for inductively degenerated cascode CMOS low-noise amplifiers (LNAs) with on-chip gate inductors. Seven different optimizations techniques are discussed. Of these, five new cases provide power match and balance the transistor noise contribution and the noise contribution from all parasitic resistances in the gate circuit to achieve the best noise performance under the constraints of integrated gate inductor quality factor, power consumption, and gain. Three of the power matched techniques (two power constrained optimizations and a gain-and-power constrained optimization) are recommended as design strategies. These three optimization techniques significantly improve the noise figures for LNA designs that are to employ on-chip gate inductors.

Minimizing the Noise Penalty Due to Mutual Coupling for a Receiving Array

For phased array receivers, mutual coupling leads to beam-dependent active impedances which must be taken into account when matching the array ports to front end amplifiers for optimal noise performance. We study the noise penalty for several noise matching conditions and develop a matching condition that minimizes the average beam equivalent receiver noise temperature over multiple beams. For non-beamforming applications such as multiple input multiple output communications, we show that noise performance for coupled arrays can be quantified using the spectrum of an equivalent receiver noise temperature correlation matrix.

Sub-0.2 dB Noise Figure Wideband Room-Temperature CMOS LNA With Non-50

This paper presents a wideband low-noise amplifier (LNA) designed to be used as the first stage of the receiver in the Square Kilometer Array radio telescope. The LNA design procedure and its layout features are discussed. The noise figure optimization procedure determines the signal-source resistance that results in reduced noise figure. When used in the radio telescope, the required signal-source resistance will be presented by the telescope custom-made antenna elements. The LNA, designed in 90 nm bulk CMOS, achieves sub-0.2 dB noise figure from 800 MHz to 1400 MHz, return loss of more than 11 dB, gain of more than 17 dB driven into a 50 load, output 1 dB compression point of 2 dBm, output IP3 of 12 dBm, and output IP2 of 22 dBm while consuming 43 mA from a 1 V supply. In the LNA implementation presented in this paper the load choke inductor and the source inductor are integrated whereas the gate-, bias-, and the choke-inductor between two transistors of the cascode are external. The noise figure of the presented LNA is to our knowledge the lowest noise figure achieved by a power matched wideband CMOS LNA at room temperature.

\Omega

This study presents new techniques for implementing continuous-time second-order band-pass filters with high-quality factors and asymmetric slopes. The techniques are centred around the realisation of two non-conventional transfer functions which include the non-integer-order Laplacian operator sα; 0<α<1. Four main possible circuit realisations; one based on a frequency-dependent negative resistor (FDNR), another based on an inductor and two based on multiple amplifier biquads (MABs) are given and verified using Spice and experimentally for both transfer functions. In addition, a field programmable analogue array (FPAA) realisation is tested and verified. Last but not least, a possible realisation using current conveyors is also given, tested and verified.

Signal-Source Impedance

A CMOS low noise amplifier (LNA) is proposed for a proof-of-concept design of the square kilometer array (SKA) radio telescope. A novel variation on a well-known source-degenerated LNA topology is introduced that allows tuning of the power match centre frequency independently from the frequency at which the LNAs noise figure approaches its minimum noise. The 0.7-1.4 GHz LNA designed in 0.18mum CMOS achieves better than 11 dB return loss with a noise temperature of 40 K, provides a power gain of 17 dB and IP1dB of -10dBm while consuming 50 mW of power from a 1.8 V supply. The design procedure of the LNA is presented and performance of the LNA is compared with previously published results

High-quality factor asymmetric-slope band-pass filters: A fractional-order capacitor approach

This paper presents an approach to measure the noise figure of a differential low-noise amplifier (LNA) based on familiar ldquocold-hotrdquo single-ended noise figure measurements. To demonstrate the usefulness of this approach, measurement results are presented for a wideband differential LNA designed to be used as the first stage of the receiver in the Square Kilometre Array radio telescope. The presented LNA achieves less than 0.41 dB of differential noise figure in the 700 MHz to 1.4 GHz band, differential S11 <-13 dB, differential S21 between 18 and 14 dB, single-ended output P1 dB of -8.2 dBm, and output IP3 of -1 dBm while consuming 81 mA from a 1.3-V supply. The approach of measuring the differential noise figure may be automated with one switch at the output of a standard noise source and one switch at the input to a standard noise figure analyzer or a noise figure meter, allowing for automated noise figure measurements of differential LNAs based on the differential pair topology.

Wide-band CMOS low noise amplifier for applications in radio astronomy

This paper compares the performance of source-tuner noise-parameter extraction methods used to measure noise parameters of low-noise amplifiers that have very low (1 dB) noise figures. The methods discussed are known as the Cold method and the modified Y -factor method (or Hot-Cold method). The paper describes equations used in the extraction algorithms. In a Monte Carlo analysis by randomly adding various sources of uncertainties to ¿measurements,¿ created with a computer simulation, performances of the noise parameter extraction methods are compared. It is shown that the iterative Cold method and the direct Cold method are the best at extracting Rn and ¿opt noise parameters in terms of lowest standard deviation and close proximity of the extracted mean values to the true values. The simplified Cold method, used in a number of commercial systems, has largest systematic offsets in extracted noise parameters while being the quickest to perform. The modified Y-factor method is the slowest to perform due to additional time required for hot measurements. This method is marginally the most accurate to extract F min. These conclusions are also supported with measurement results. This study assembles in one place necessary theoretical background information to serve as a reference for those who are working in the field of noise parameter extraction using tuner-based methods.

A Technique for Differential Noise Figure Measurement of Differential LNAs

Design and measurements of a room temperature 700 MHz - 1400 MHz low noise amplifier (LNA) in 90-nm bulk CMOS, intended for use in the Canadian large adaptive reflector (CLAR) radio telescope, are presented. The new bandwidth constrained LNA noise figure optimization and broad-banding technique as well as the importance of substrate shielding are discussed. The amplifier has 0.35 dB noise figure while consuming 45 mW of power from a 1-V supply and achieves output P1dB of -5.3 dBm and output IP3 of 7.5 dBm with the gain (S21) ranging from 20.5 dB to 16.3 dB across the band. The LNAs input and output impedances are matched to 50 Omega. The LNA represents the first CMOS design that satisfies the very demanding requirements of radio telescopes. The topology and optimization presented in this paper are not limited to radio astronomy applications and can be applied for wide band commercial applications such as tri-band GSM operating in the 850 MHz - 1900 MHz frequency range

Evaluation of Tuner-Based Noise-Parameter Extraction Methods for Very Low Noise Amplifiers

A continuous-time (CT) radio frequency (RF) antenna array beamformer and analog circuit based on a discrete-space-continuous-time (DSCT) 2-D fan-filter having transfer function H_F,A(z_x,s_ct) is derived. The proposed transfer function is based on a 2-D FIR discrete domain fan filter. The discrete domain prototype is converted to the proposed mixed-domain DSCT analog filter by replacing unit sampled delays with CT analog first-order all-pass networks corresponding to the bilinear transform. First-order all-pass network Φ(s_t) is a poor approximation to a CT delay exp(-<i>sT</i>) . To address this, a novel broadband pre-warping method is proposed to exactly compensate for such “bilinear warping”. A 65 nm CMOS VLSI circuit for Φ(<i>s</i>_t) is proposed and an example fan filter with axis oriented at θ₀=35^°, half-fan-angle ε = 5^° and maximum frequency <i>F</i>_u = 2.6 GHz is simulated employing closed-form expressions, an ABCD parameter based model and 65 nm CMOS simulations in Cadence. A stop-band interference rejection of 38 dB is verified by BSIM4 based simulations. The proposed circuit for Φ(<i>s</i>_t) operates at 3.7 mA from a 1.2 V supply. The beamfomer is shown to operate correctly in the presence of PVT variations of Φ(<i>s</i>_t).

Wide Band Room Temperature 0.35-dB Noise Figure LNA in 90-nm Bulk CMOS

A 4-bit 65nm time-based analog-to-digital converter (ADC) targeting the next-generation Square Kilometre Array (SKA) is presented. This ADC is composed of an analog voltage-to-time converter (VTC) front end and a digital time-to-digital converter (TDC) back end. The two components can be physically separated to minimize the impact of digital noise from the ADC on high-gain, high-sensitivity receiver chains common in radio telescopes. At a sampling rate of 5 GS/s the ADC consumes 35 mW from a 1 V supply. After calibration, the ADC achieves a peak SNDR of 22.9 dB, SFDR of 34.0 dB and ENOB of 3.5. At the ERBW of 2100 MHz, SNDR is 18.4 dB, SFDR is 22.3 dB and ENOB is 2.8. The resulting worst-case figure of merit is 1.0 pJ/conversion. This is the highest reported sampling rate for a time-based ADC to date.