You don’t want to burden your design with the extra cost of a higher-resolution analog-to-digital converter (ADC). But because of board-space limitations, adding an external ADC may not be acceptable. Fortunately, you can get 10-bit performance with an 8-bit ADC by implementing triangular dither.

Check out these additional letters to and answers from electronics guru Bob Pease.

Only two wires are needed to connect the 105-Msample/s LTC2274 ADC to an FPGA, reducing board space and decreasing noise and crosstalk. The serial interface can reach 2.1 Gbits/s, and it’s compatible with FPGAs like the Xilinx Rocket IO, Altera Stratix II GX I/O, and Lattice ECP2M I/O.

Several MOSFETs with higher breakdown voltages have hit the market. Some are rated for 40, 60, and 80 V, which is 10 V higher than existing devices in their respective classes, with significantly lower conduction losses. Others are rated for 900 V, again with improved conduction loss specs. At the high end of the breakdownvoltage range, Infineon Technologies is pushing the envelope with the industry’s first 900-V superjunction MOSFETs ...

You don’t want to burden your design with the extra cost of a higher-resolution ADC. And because of board-space limitations, adding an external ADC may not be acceptable. Fortunately, you can get 10-bit performance with an 8-bit ADC by averaging multiple samples. This process is called oversampling.

HI BOB, I have been collecting some new but mostly museum-grade test instruments. Along with purchases from various instrument rental houses, flea markets, and so on, for a while I bid on items in government liquidation auctions. Occasionally, I won. The starting bid was always $50, and some I got at that price. Some went way higher but seldom approached the original list price, and I gave up way before that. Often, the shipping costs to a pickup and forward...

It’s possible to build a push-pull amplifier using amplifier ICs, rather than discretes, as in the traditional class B amp (see the figure). A bridged-amplifier configuration effectively doubles the voltage swing at the load. It’s also possible to build a bridge amplifier in which one stage drives one side of the speaker and a second unity-gain inverting amplifier drives the other side of the speaker. However, the...

The HVVFET is the brainchild of HVVi chief technology officer Bob Davies, one of the key inventors of LDMOS 15 years ago. Devices utilize a vertical FET structure (something that’s been tried before) because it provides higher power density than lateral devices. The problem with those early efforts were the parasitics associated with silicon substrates. That limited operating frequencies. For HVVi, Davies came up with a novel edge termination structure and a unique gate-drain ...

Amplifiers are fundamental circuit-design elements. They drive everything from earbuds to antennas. Placed ahead of analog-to-digital converters (ADCs), they reshape signals from sources as diverse as strain-gauges to ultrasound probes. Through proper selection of feedback passives, they can be configured into high-pass, low-pass, band-pass, and band-elimination filters. Feed them with multiple signals, and they produce harmonic series of all the...

The mainstream media may call it a digital age. But today’s gadgets still need integrated circuits that can transform analog signals—which convey information about “real world” phenomena like temperature, pressure, sound, and speed—into digital form. Linear Technologies is one of the leading companies designing, manufacturing, and marketing a broad line of standard high-performance analog integrated circuits as well as devices that control power and regulate voltage in...

In designing a simple spectroscopy setup, we needed to synchronize the speed of a small, inexpensive dc motor precisely to 6000 rpm (100 Hz). Our first idea was to take a phase-frequency detector type of phase-locked loop (PLL), the CMOS 4046, to maintain not only the speed, but also the phase to the reference signal. 1 In the classical approach, the motor’s speed is modeled as a firstorder time delay over time. Some math is done to obtain a good ...

The circuit shown in the figure can monitor resistance in a noisy or otherwise hostile environment. A 1:1 transformer provides isolation and a good common-mode rejection ratio (CMRR). The resistance across the secondary winding is reflected to the primary, where it forms a voltage divider with resistor R1 (see the figure). This divider produces a reducedamplitude clock signal that's coupled through C2, rectified by ...

The most common method for interfacing multiple switches—multiplexing— allows for the connection of (N/2)2 switches with N microcontroller IO lines. The method described below, which has its roots in an LED interface technique commonly known as “Charlieplexing,” makes it possible to interface N*(N – 1) switches with N IO lines. In conventional multiplexing of an N-by- N matrix with 2N IO lines, half of the lines are configured for input and...

This circuit creates a set of LED-based electronic birthday candles that are just as much fun as blowing out wax candles, but are also reusable, scalable, and even eco-friendly. It uses a thermal sensor that’s maintained at a temperature above the ambient temperature. When you blow air over the sensor, the resistance changes. The circuit detects this change and turns off the eight LEDs. When you stop blowing, all but one of the LEDs turn on. This cycle...

Adding “intelligence” to measurement systems has become commonplace because 8-bit microcontrollers are inexpensive and widely available, and they can be programmed in many of today’s popular higher-level languages (e.g., C and Basic). Often, the main challenge is signal- conditioning the sensor’s output into a signal-ended voltage that can fully exploit the input span of the microcontroller’s analog-to-digital converter (ADC). By using basic math and a...