Barrie Gilbert

A new wide-band amplifier technique

Precision dc-coupled amplifiers having risetimes of less than a nanosecond have recently been fabricated using the monolithic planar process. The design is based on a simple technique that has a broad range of applications and is characterized by a stage-gain- bandwidth product essentially equal to that of the transistors, and a very linear transfer characteristic, free from temperature dependence.

The MICROMIXER: a highly linear variant of the Gilbert mixer using a bisymmetric Class-AB input stage

This paper outlines the basic theory of a development of the Gilbert mixer. The bipolar junction transistor (BJT) differential pair widely used as the RF input stage is replaced by a bisymmetric Class-AB topology based on translinear principles. It does not have inherent gain compression, affording a greatly extended signal capacity. The linearity of variants of the basic form is excellent, providing two-tone intermodulation intercepts as high as +30 dBm, without the expenditure of high bias currents. It can operate on supplies as low as 2.2 V, with a power consumption of under 5 mW. The input impedance of this mixer is accurately controllable (typically 50 /spl Omega/) and provides a true broadband match. The noise figure depends on design details and is generally not as low as in mixers specifically optimized for noise performance, although acceptable for many receiver applications. Inductively degenerated variants can be tuned to a narrowband match at microwave frequencies and provide full-mixing SSB noise figures as low as 6.5 dB, Practical realizations are in use in applications to 1.9 GHz.

Translinear circuits: an historical overview

The concept of a translinear circuit is now widely appreciated and applied. This paper traces the history of the concept, delineates the original meaning of the term, explains the basic principles of this class of circuit and discusses recent, more general, interpretations of the term. It is recommended that the word translinear, used without further qualification, should be reserved exclusively for those cells invoking exponential device behaviour, which applies to all bipolar transistors, including heterojunction types, and to MOS transistors operated in the subthreshold, or weak inversion, domain, but does not apply to normal MOS operation in strong inversion. It is proposed that the theory and practice related to such ‘quadratic’ operation of MOS devices, where the transconductance is presumed to be linear with gate-source voltage, should be termed voltage-translinear, or VTL.

A monolithic 16-channels analog array normalizer

A monolithic circuit has been developed which accepts 16 parallel voltage inputs having values which may be as small as 15 mV or as large as 15 V, and generates 16 concurrent output voltages which are in the same ratios as the inputs with a peak amplitude controllable by the user. Response time is in the region of 1 /spl mu/s at full scale. The chip includes provisions for expansion to any number of channels. Operation is from supplies of /spl plusmn/3 to 15 V at a quiescent current of 125 /spl mu/A. Details of the design principles and peripheral circuitry are provided. Measurements of static accuracy and dynamic performance demonstrate that this approach may often simplify preprocessing of signal arrays in pattern-recognition applications.

A new technique for analog multiplication

Describes a new method using emitter current crowding for performing accurate multiplication of analog signals using devices of special geometry but capable of fabrication with a standard bipolar process. A narrow region of current injection-a carrier domain-can be positioned on an emitter by one electrical input and controlled in magnitude by a second input. The resistive epi layer resolves this current into a differential output proportional to the product of the inputs. A key advantage of these multipliers is their low noise. The basic principle can be applied to many other nonlinear operations. A two-quadrant and a four-quadrant multiplier are described.

Monolithic voltage and current references: theme and variations

The Theme is that of the ‘bandgap voltage reference principle’, The Variations are some unusual and hitherto unpublished derivatives of the form. Most are of moderate to high accuracy, and generally intended for operation in a low-voltage commercial context, which typically means a minimum supply of 2.7V and a minimum temperature of-30°C. In some cases, the supply may be as low as 1.2V and operation may be required at temperatures of-55°C, though rarely in combination. A few are very simple, and useful where accuracy is needed only over a narrow supply range. The emphasis throughout is on allbipolar, and in many cases, all-NPN, realizations, while acknowledging that complementary bipolar and BiCMOS processes often provide implementation advantages. Brief mention will be made of the special challenges of realizing voltage References in an all-CMOS process; a dynamic reference, interesting and valuable because it requires only a single junction device, is described.

Analog at milepost 2000: a personal perspective

Electronics has barely just begun to exploit the endless opportunities for analog techniques. Rather than rendering them obsolete, the recent explosion in digital communications systems has only increased the demand for both fully analog and mixed-signal integrated-circuit (IC) products. This paper is an unashamedly personal and bipolar-centric review of a few selected aspects of the contemporary landscape and offers several reasons for expecting an unending dependence on analog techniques.

A calibrated RF/IF monolithic vector analyzer

This work presents the first monolithic integrated circuit that provides precise, scaled measurements of gain and phase difference between two signals up to 3 GHz. A 60 dB gain range and 180 degree phase range are achieved with 30 mV/dB and 10 mV/degree scaling, respectively. This function has wide application for in-situ measurement of vector RF parameters and in linearization of transmission systems such as power amplifiers.

Introduction To "The Transistor- A New Semiconductor Amplifier"

It was a great pleasure to revisit one of the papers written during the dawn of the transistor age. This paper was first presented at the Winter General Meeting of the American Institute of Electrical Engineers (AIEE) in New York in early February 1949, the same month as the launching of the first U.S. rocket to enter space, loaded with transistorless telemetry. Recent publications [1], [2] are helping us to see more clearly how this semiconductor device came into being, how it was characterized, and how it was nicely named [3], albeit on the basis of a questionable rationale. The pregnant title, “The Transistor—A New Semiconductor Amplifier,” was arresting while at the same time curiously modest. The use of the indefinite article might have suggested that this frail and tentative device was merely one of a broad portfolio of contemporary developments related to amplifiers—“new” in the sense of “another.” In fact, there were no other contenders; the “crystal triode” was special. Nevertheless, at its publication, this paper would scarcely be recognized as one of the strident notes in the brilliant fanfare that was about to usher in profound changes for all human endeavor and shape life on Earth so powerfully and irreversibly. At the time of this paper’s publication, both Becker and Shive (Fig. 1) were at Bell Labs. Being a part of this history, the paper has more than clinical interest to me. Sometime during 1954, while working at my first job at the carefully hidden Signals Research and Development Establishment (SRDE), perched on the chalk cliffs of the English Channel, I lapsed into a reckless love affair. I suppose it was inevitable. I was young and impressionable, and these things happen, as they say. The object of my devotion was petite, black, with three legs, and had a heart of germanium. Though the decades have slipped by, I still hold her captive, with many of her kin, in the museum drawers of my home laboratory.

101 ways to make a circuit fail

A circuit design, whether on first silicon, breadboarded or PCBs will quite often fail to work first time and getting it to work is costly time-consuming, irritating and sometimes very frustrating. If the failure is inevitable, then why are more precautions not taken at the earlier stages of design? What are these mystical failure mechanisms? Human errors, simulation errors, testing errors? etc. The authors attempt to answer some of these questions.<<ETX>>