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Simple Circuit Provides Adjustable CAN-Level Differential-Output Signal

The controller area network (CAN) serial-bus topology allows devices and microcontrollers to communicate with each other without a host computer. Featuring arbitration-free transmission, it places a controller and a host processor at each device node, eliminating the more complex wiring harness that would be necessary to interconnect devices with a host computer.

High-Temperature Electronics Pose Design and Reliability Challenges

Many industries need electronics that can operate reliably in harsh environments, including extremely high temperatures. Traditionally, engineers had to rely on active or passive cooling when designing electronics that must function outside of normal temperature ranges, but cooling may not be possible in some applications, or its high cost and low reliability may make it undesirable in others.

Low-Noise, Gain-Selectable Amplifier

Traditional gain-selectable amplifiers use switches in the feedback loop to connect resistors to an amplifier, but the switch resistance degrades the noise performance of the amplifier, adds significant capacitance on the inverting input, and contributes to nonlinear gain error. This article presents a gain-selectable amp that uses an innovative switching technique that preserves the noise performance while reducing the nonlinear gain error.

Modern DACs and DAC Buffers Improve System Performance, Simplify Design

As the heart of many instrumentation and control systems, digital-to-analog converters (DACs) play a key role in determining system performance and accuracy. This article looks at a new precision, fast-settling, voltage-output 16-bit DAC and shows some ideas for buffering the outputs of high-speed complementary current-output DACs that can rival transformer performance.

Designing a Low-Power Toxic Gas Detector

Safety first! Many industrial processes involve toxic compounds, including chlorine, phosphine, arsine, and hydrogen cyanide, so it is important to know when dangerous concentrations exist.This article describes a portable carbon monoxide detector using an electrochemical sensor. CO is relatively safe to handle, but it is still lethal, so use extreme care and appropriate ventilation when testing the circuit described here.

Robust Amplifiers Provide Integrated Overvoltage Protection

Faulty performance or damage can occur when an op amp’s input voltage exceeds the specified input-voltage range. This article discusses some common causes and effects of overvoltage conditions, how cumbersome overvoltage protection can be added to an unprotected amplifier, and how the integrated overvoltage protection of newer amplifiers provides a compact, robust, cost-effective solution.

Efficient FSK/PSK Modulator Uses Multichannel DDS to Switch at Zero Crossings

This article describes how two synchronized DDS channels can implement a zero-crossing FSK or PSK modulator. In phase-coherent radar systems, zero-crossing switching reduces the amount of post processing needed for target signature recognition; and zero-crossing switching reduces PSK spectral splatter. Here, the AD9958 two-channel complete DDS is used to switch at the zero crossing.

DDS Devices Generate High-Purity Waveforms Simply, Efficiently, and Flexibly

Direct digital synthesis (DDS) technology is used to generate and modify high-quality waveforms in a broad range of applications in such diverse fields as communications, defense, medicine, industry, and instrumentation. This article provides an overview of the technology, describes its strengths and limitations, looks at some application examples, and showcases some significant new products.

How to Apply DC-to-DC Step-Up/Step-Down Regulators Successfully

High efficiency dc-to-dc converters come in three basic topologies: step-down (buck), step-up (boost), and step-down/step-up (buck/boost). The buck converter is used to generate a lower dc output voltage, the boost converter is used to generate a higher dc output voltage, and the buck/boost converter is used to generate an output voltage less than, greater than, or equal to the input voltage.

Oversampled ADC and PGA Combine to Provide 127-dB Dynamic Range

The need to measure wide dynamic range signals is common, but current technology often has difficulty meeting system requirements. This article presents an alternative that uses a high-speed, successive-approximation ADC, combined with an autoranging programmable-gain amplifier front end with gain that changes automatically based on analog input value to provide a dynamic range of more than 126 dB.

Advanced Data Converters

Advanced Data Converters offers a stimulating cornucopia of circuit techniques, ideas, and examples, profusely illustrated and supported with extensive documentation by some 416 references to the literature—a veritable catalog of design concepts.