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The methods of handling small signals from multidecade sensors are discussed. A simple, fast and accurate preprocessing amplification unit (PPU) with the capabilities of automatic gain switching is presented. The unit could be used in the analog channels of a computer based data acquisition and process control system. The use of such a unit with some of the analog sensors would increase the resolution of the measuring subsystem involved through the combined action of a shared analog-to-digital converter (ADC). The PPU consists of an operational amplifier with suitable performance, a resistance feedback network whose value could be changed by switching, and FET switches. The switching control is done by a reversible counter, decoder, and state control logic all using TTL chips. A digital code representing the gain constant is available together with the amplified signal. An experimental unit was built for use in a wide range, neutron flux, measuring channel. This channel is connected to the control computer's analog subsystem which has a 10 bit ADC. Accuracies better than 0.1% of full scale on the most sensitive range (10-9 amp.) and switching speeds less than 1 ?.sec. are obtainable. The accuracy limits are imposed by the quality of a single amplifier, and the speed limits by the amplifier slew rate and the delay in a few IC logic chips.

The state of the art in monolithic operational amplifier design is surveyed. A set of large- and small-signal performance parameters are defined and discussed. Relationships between the important operational amplifier parameters of slew rate, offset voltage, and unity gain bandwidth are demonstrated. The dependence of settling time upon the fine structure of the open-loop frequency response is discussed, and the recent technological and circuit design approaches to the minimization of settling time are reviewed.

A study is made of the integrated circuit operational amplifier (IC op amp) to explain details of its behavior in a simplified and understandable manner. Included are analyses of thermal feedback effects on gain, basic relationships for bandwidth and slew rate, and a discussion of pole-splitting frequency compensation. Sources of second-order bandlimiting in the amplifier are also identified and some approaches to speed and bandwidth improvement are developed. Brief sections are included on new JFET-bipolar circuitry and die area reduction techniques using transconductance reduction.

In active RC networks certain nonlinear phenomena may occur due to the nonlinear properties of the amplifiers. It is shown that one of these, the slew rate limitation, may give rise to the jump phenomenon. The class of networks to be studied are described by a third order nonlinear differential equation. The theoretical and experimental results are found to correspond well.

The methods of handling small signals from multi-decade sensors are discussed. A simple, fast and accurate preprocessing amplification unit (PPU) with the capabilities of automatic gain switching is presented. The unit could be used in the analog channels of a computer based data acquisition and process control system. The use of such a unit with some of the analog sensors would increase the resolution of the measuring subsystem involved through the combined action of a shared analog-to-digital converter (ADC). The PPU consists of an operational amplifier with suitable performance, a resistance feedback network whose value could be changed by switching, and FET switches. The switching control is done by a reversible counter, decoder, and state control logic all using TTL chips. A digital code representing the gain constant is available together with the amplified signal. An experimental unit was built for use in a wide range, neutron flux, measuring channel. This channel is connected to the control computer's analog subsystem which has a 10 bit ADC. Accuracies better than 0.1% of full scale on the most sensitive range (10 -9 amp.) and switching speeds less than 1 u. sec. are obtainable. The accuracy limits are imposed by the quality of a single amplifier, and the speed limits by the amplifier slew rate and the delay in a few IC logic chips.

An internally compensated monolithic operational amplifier, fabricated using only junction-isolated bipolar processing, slews in excess of 500 V//spl mu/s, and settles to within 0.1 percent in 200 ns as a pulse inverter. Performance in the noninverting mode is only slightly degraded in comparison with the inverting mode. In addition, the following performance levels have been achieved: 50-MHz unity-gain bandwidth with 96-dB open-loop gain, 30-mW quiescent power at /spl plusmn/3 V, /spl plusmn/50-mA output current capability, and output voltage to within 0.5 V of either supply. In order to achieve the above performance, the following innovations were made: 1) a process for junction-isolated compatible complementary p-n-p transistors with low collector series resistance, 2) a high-speed class-B output stage, 3) push-pull middle stages, 4) driven internal reference voltages locked to the noninverting input, and 5) very small voltage drops across large internal shaping capacitors which permit use of high-capacitance junctions.

An operational amplifier capable of operating with power supplies up to /spl plusmn/40 V is discussed. The device exhibits output voltage and input common mode swings to within a few volts of either power supply, has an input offset current of 1 nA, a slew rate of 2 V//spl mu/s, and is internally compensated. This paper describes special circuit and device techniques used to reliably fabricated this amplifier with essentially standard monolithic diffused technology.

This paper covers some important advances in understanding the problems associated with the VOR system, especially in connection with area navigation. Anomalies arising from airborne equipment, operating in the airborne environment, are described and analyzed. Factors contributing to overall system accuracy are treated with respect to VOR receiver response and to rate-limiting, filter means, with special attention to appropriate noise reduction systems providing zero or minimal time delay characteristics. The use of active filters in the VOR receiver is shown to be of major importance with regard to signal improvement and overall system accuracy. Active filters of the constant slew rate type have proved of significant value, both within the VOR receiver as well as in signal processing.

A single-chip (67/spl times/90 mil) integrated-circuit operational amplifier using thin-film resistors and super-gain transistors has been designed to achieve dc follower accuracies of 0.001 percent with 100-k/spl Omega/ source resistance. The circuit achieves gains of 140 dB using thermally balanced layout designs for both input and output stages, nulled drifts of 0.3 /spl mu/V//spl deg/C, and offset currents well under 1 nA. All other dc specifications including power-supply variation error (PSRR), common-mode gain error (CMRR), etc., are in the 1-10 ppm error range; and a procedure is given by which long-term drifts of less than 10 /spl mu/V/month can be assured. AC performance is comparable to general-purpose integrated-circuit operational amplifiers, i.e., f/SUB t/=300 kHz and slew rate of 1.2 V//spl mu/s at gain of ten. The circuit is externally compensated for unity gain with a single 390-pF capacitor and is fully input and output protected.

An internally-compensated monolithic low-power (50mW) operational amplifier with slew rates of ±500 V/μs and settling times of 0.1% in 200 ns, using junction-isolated, bipolar technology, will be described.

A technique for the fabrication of p-channel MOS transistors and bipolar transistors within monolithic integrated circuits is described. Total process compatibility has been achieved without compromising either the n-p-n bipolar or p-channel MOS characteristics. The technology developed is similar to that used for conventional integrated circuits until the channel oxidation step, A low temperature oxidation followed by a high temperature anneal process that produces negligible changes in preceding diffusion profiles was used to form this oxide. Bias temperature tests of MOS capacitors have shown the oxide to be reproducibly free of contamination. A high slew rate MOS bipolar operational amplifier has been designed and fabricated on 0.045- by 0.045-in chip using the new technology. Typical characteristics are slew rate =80 V/µs voltage gain = 70 dB. The MOS transistors are used as active loads and level shifters in this circuit and provide a much improved frequency response over conventional circuits using p-n-p lateral transistors.

A compatible complementary pnp transistor with usable breakdown voltage has been developed which allows a significant improvement in the slew rate of monolithic integrated circuit amplifiers with low to moderate standby power. Monolithic circuits with high speed npn's and lateral pnp's can be made with high slew rates, but only at the expense of standby power. As this power becomes too large to remove from the chip, the performance is limited. Compatible, complementary pnp's allow the node capacitances to be charged with high currents with low standby power, thus allowing a significant increase in circuit performance. The triple diffused vertical pnp's reported earlier are not acceptable in amplifiers because of the low collector-emitter breakdown of approximately 7.5 volts. A similar acceptable two epi process has been reported using diffusion, however, the process described herein provides much tighter control on device parameters.

A power amplifier designed for use as a biological stimulator is described. It is driven by a dc voltage or a pulse generator with an amplitude of 50 volts. The output power of up to 250 volts and 100 ma is precisely controlled. The rise time is less than 5 ?sec. A dual-channel version whose outputs may be independently controlled and mixed is also described. The circuit for the +400 volts and ?300 volts regulated power supplies is shown.

A monolithic IC operational amplifier that provides high speed in inverting applications has been developed. Full-power bandwidth of 2 MHz, open-loop gain of 300 at 1 MHz and stable response with capacitive load have been achieved.

An electronic subsystem has been developed which directly plots isodose contours on an X-Y recorder. All mechanical linkages such as selsyn servos, gears, cams, and switches are eliminated. The circuit response time is better than 1 ms, and therefore plotting time is limited only by detector response and X-Y recorder slew rate. Integrated circuit and printed circuit technics have been utilized, thus allowing the system, exclusive of power supplies and meters, to be placed on four 4 × 5-inch plug-in printed circuit boards. The circuit is fundamentally an analog-to-digital converter, utilizing ten window detectors to convert a normalized input detector signal to an electronic switch closure for each of 10 input signal levels. The ten dual comparators are calibrated to produce an output at each of ten 10 per cent increments and an associated window width of 0.5 per cent. The switch closure is plugged into the Z axis or pen actuator of the X-Y recorder. Potentiometers on the scanner drive the X- and Y-coordin...

A high-speed junction-isolated op amp using a novel split-band configuration, a new input current cancellation circuit and ion-implanted components will be described. A 10-MHz bandwidth, 10 V/μs slew rate and 35-nA input current have been achieved.

An inexpensive wide-band amplifier suitable for driving many piezoelectric transducers encountered in underwater sound propagation studies and laser research is described. Small signal bandwidth is dc to 5 MHz, with large signal response determined by a slew rate limit of 800 V/??s, at maximum output voltage and current of 280 V peak-to-peak and 1 A.

Methods to determine quantitatively the dynamic response of automatic ellipsometers to variations in the optical properties of a specimen have been developed and are illustrated by data from a newly built ellipsometer. The quantities determined include slew rate, frequency response, accuracy, and resolution. The methods are based on the use of rotating mirrors for the generation of well-defined, fast optical changes in the reflecting surface.

A method of doubling the output-voltage swing and to increasing the slew rate of an operational amplifier is described. Two practical circuits and experimental results are given.