Analog Devices Offers ADCs For Utility Substation ControlMay 27, 2009 by Jeff Shepard
Analog Devices, Inc. introduced simultaneous-sampling ADCs (analog-to-digital converters) that are said to simplify the design of next-generation power-line-monitoring systems. According to the company, the need for more efficient utility substations and "smart grid" management is growing as worldwide electricity demand increases. Electric utility companies need power-line-monitoring systems to monitor and control energy consumption, cost, and quality, as well as to protect expensive equipment from power surges and severe storms.
"ADI’s new simultaneous-sampling ADCs provide the resolution and performance needed for next-generation power-line-monitoring system designs that ensure the reliable delivery of electricity to millions of people in nearly every corner of the world," said Leo McHugh, Product Line Director, Precision Signal Processing, Analog Devices. "ADI offers a broad range of semiconductor solutions that solve design challenges in every part of the energy monitoring system, ranging from the electricity meter to the substation."
Also available in six- or four-channel options, ADI’s 16-bit, eight-channel AD7606 and 14-bit, eight-channel AD7607 simultaneous-sampling ADCs achieve SNR (signal-to-noise ratio) performance of 90 dB. The optional oversampling mode further improves SNR performance, reduces code spread, and enhances anti-alias rejection. Multi-channel integration facilitates three-phase I&V (current and voltage) measurement and neutral monitoring in substation equipment. This enables power-line monitoring systems to observe and manage abnormal events occurring on a power grid, such as electrical faults or short circuits. The AD7606 and AD7607 simultaneous-sampling ADCs operate on a 5V analog supply, 1.8 to 5V logic supply, and feature a front-end, anti-alias filter with high input impedance and input clamp to ±16.5V. In addition, an internal reference and a reduced decoupling capacitor requirement provide a higher level of integration compared to alternative solutions. The new devices offer true bipolar analog input ranges of ±5V and ±10V that allow for the preservation of phase information while sampling bipolar voltages and currents over a wide dynamic range.
The AD7606 and AD7607 simultaneous-sampling ADCs contain on-chip LDOs (low-drop-out regulators), a reference and reference buffer, track-and-hold circuitry, signal-conditioning circuitry, on-chip conversion clock, and high-speed parallel and serial interfaces. The new devices also feature low-noise, high-input-impedance (independent of sample rate), signal scaling amplifiers that provide 10-kHz input bandwidth (-3-dB), and 1 M analog input impedance with only 0.1% gain error, and 0.01% offset error. The AD7606 and AD7607 simultaneous-sampling ADCs integrate a front-end, anti-alias filter with attenuation of approximately 40 dB while sampling at a fast throughput rate up to 200 kSPS. The conversion process and data acquisition are controlled using CONVST signals and an internal oscillator. Two CONVST pins allow the simultaneous sampling of all eight analog inputs or two groups of four analog input channels to allow for phase differences between transformers.
The units are priced as follows (each, per 1,000): AD7606 at $23.10 and AD7607 at $18.48.