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.

High-side current-sense amplifiers are used in a wide variety of applications where reliability and accuracy are paramount concerns. In computer notebooks, these devices monitor the battery’s charge and discharge currents, as well as currents in USB ports and many other supply rails that may need to be powered down to control heating and power dissipation.

Designed in collaboration with SiRF Technology Inc., austriamicrosystems’ new AS3650 power and audio management unit is an excellent fit for personal navigation devices (PNDs) using SiRF’s navigation processors. The AS3650 is a highly integrated device that includes power management, battery management, linear and USB charging, a backlight driver for various screen sizes, and a touch-screen interface.

One day, back about 1966, I was going up the elevator at 285 Columbus Avenue in Boston to look at some production problems on Philbrick’s fifth floor. And who was in the elevator, but George Philbrick’s friend Jim Pastoriza. Jim was going up to show George his new analog computer demonstrator—portable and battery-powered. In fact, it was running, and he gave me a demo right on the elevator as we ascended. And, this modular analog computer ran on a couple of...

As an application engineer, I spend a lot of time convincing customers that a delta-sigma modulating analog-to-digital converter (ADC), or DSM, would be the best choice for their particular application. Then they come up with all sorts of excuses for why they prefer a successive-approximation ADC. I’ve come to the conclusion that they prefer successiveapproximation ADCs because they fundamentally don’t understand how a DSM works, perhaps because DSMs involve...

Communications channels used to be a challenging exercise in pure analog design. Today, modulation occurs in the digital domain in many systems. But the transmitted signal is analog, so there’s always a conversion. For any communications system, choices for the digital- to-analog converter (DAC) and its current-to-voltageconverting op amp depend on the required bandwidth. As DACs and op amps get faster, they move closer to the transmitting...

Single Chip Digitizes High-Side Power Measurements In-circuit power measurements frequently involve a currentsense amplifier or a hot-swap controller and an analog-todigital converter (ADC). Optimally, the current sensing is done on the high side of the load to avoid false grounds. But one problem with that approach is the presence of a high common-mode voltage on the amplifier input. Another is the typical ADC’s limited input voltage range. In addition, the cost of...

There are now two sources of analog front ends (AFEs) for ultrasound applications. Texas Instruments is sampling the AFE5805, the first member of a future family for portable to high-end ultrasound diagnostic equipment. Last year, Analog Devices introduced the AD9271 for the same market. Functionally similar, both are octal devices that incorporate a lownoise amplifier, variable gain amplifier (VGA), anti-aliasing filter, and 12-bit analog-to-digital...

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...

Telecom and data-communications equipment commonly use small-formfactor pluggable (SFP) modules for the physical-layer interface. Also common in these systems is an I2C bus for the management data input/output (MDIO) interface. But when several SFP modules are used, they all have the same I2C address. As a result, they can't all connect to the same I2C bus. To avoid the need for multiple I2C bus masters in that situation, ...