A/D convertors designed for high voltages

Analog Devices has introduced six 12 to 16bit true bipolar, multichannel analogue-to-digital convertors (ADCs) for high-voltage applications.

Analog Devices is augmenting its broad portfolio of world-leading data conversion products with the introduction of six 12 to 16bit true bipolar, multichannel analogue-to-digital convertors (ADCs) for high-voltage applications.

These ADCs provide higher speed and accuracy, reduce power consumption by 60% and require fewer external components, making them ideal for industrial and instrumentation applications that use high-voltage (+/-10V) signals, such as oscilloscope test functions, motor control, voltage drives, power line monitoring and channel test tools for pipeline inspections.

The convertors, which are manufactured on Analog Devices' iCMOS industrial process technology, are designed to meet the industrial sector's growing demand for higher resolution and channel counts, faster conversion times, and lower power consumption.

The AD7328 13bit (12bit plus sign) ADC features the industry's fastest throughput rate (1Msample/s), eight-channel sampling, and power consumption of only 25mW.

The AD7656 16bit ADC offers simultaneous sampling on six channels and twice the accuracy of comparable devices (+/- 4LSB maximum INL) at 250Ksample/s per channel.

"With the introduction of these ADCs, Analog Devices is seeking to modernise the design of high-voltage industrial applications by enabling major performance advantages over traditional solutions that are power hungry and have limited throughput?, said Mike Britchfield, Product Line Director for Precision Convertors, Analog Devices "Through the use of advanced design and process techniques, we continue to deliver innovative data conversion products that offer the critical combination of speed, accuracy and power required for design success in today's most demanding industrial design environments?.

The AD7328 features 13bit resolution (12bit plus sign) - providing an extra bit of resolution for higher accuracy - and a high speed serial interface that can operate at throughput rates up to 1Msample/s.

The AD7328 consumes only 25mW and has several power-down modes that reduce its power consumption at lower throughput rates.

The AD7328 combines a number of unique features that enable greater ease of use and design efficiencies over the closest comparable solutions.

The device has high impedance analogue inputs, easing driving requirements compared to ADCs that have resistive inputs.

The increased input signal range of the ADC minimises the effect of noise at the ADC input.

Software selectable input ranges eliminate the need for level shifting or signal conditioning circuitry, reducing the cost and number of external components.

Changing the analogue input range can be accomplished without changing the hardware.

The AD7328 offers three bipolar input ranges: +/-10, +/-5, +/-2.5V and a 0 to 10V unipolar input range, all of which are software selectable.

In addition, application of a 3V reference allows the ranges to be expanded by 20%.

A channel sequencer enables multiple channels to be converted with minimum processor overhead.

Each channel can be independently programmed to one of the input ranges using the on-board range registers.

A four-channel part (AD7324) and two-channel part (AD7322) offering the same features as the AD7328 are also available.

The AD7656 is highly integrated, with six 16bit successive-approximation ADCs offering 4LSB maximum INL and fast throughput rates (250Ksample/s per channel) - plus a 2.5V internal reference and reference buffers - all housed in one package.

At 160mW, the part also enables a 60% reduction in power consumption compared with the closest comparable bipolar ADC.

The AD7656 contains low noise, wide bandwidth track-and-hold amplifiers that can handle input frequencies up to 8MHz.

The AD7656 has high-speed parallel and serial interfaces, allowing the device to interface with microprocessors or DSPs.

When in serial interface mode, the AD7656 has a daisychain feature that allows multiple ADCs to connect to a single serial interface.

The pin-compatible AD7657 and AD7658 offer the same features as the AD7656, but at 14 and 12bit resolutions, respectively.

The AD7328 and AD7656 ADCs and their derivatives, which are all sampling now, are scheduled for full production in May 2005 and July 2005, respectively.

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