Tuesday, October 24, 2006

Analog - Low-power data conversion technology enhances portability

Designed to increase the portability of patient and industrial monitors and improve the performance and throughput of automated test equipment (ATE) and data acquisition systems, Analog Devices' AD7980 1-MSPS (mega-sample per second) 16-bit ADC consumes 80 percent less power and board space than the closest competing 16-bit ADC in its class.

"Power consumption is one of the dimensions of data converter performance that receives a lot of attention at ADI," said Dick Meaney, vice president of Precision Signal Processing, Analog Devices. "Offering five times lower power per conversion, combined with outstanding AC and DC linearity, the AD7980 will afford remarkable benefits to end users across many varied applications."

Increasing Patient Comfort - The small package size and reduced power consumption of the AD7980 lends it to the design of lightweight, wearable electrocardiograms (EKGs), blood pressure monitors, oxygen sensors and other medical instruments that wirelessly transmit patient information to a data centre or nurses' station. Such mobility increases patient comfort by allowing them to wear PDA-sized monitors and eliminating the need to push bulky medical equipment when moving around the hospital.

Faster and More Accurate Industrial Instruments - In industrial equipment, the fast sampling rate and low power consumption of the AD7980 allow designers to place critical components closer together to improve system performance and speed. In today's ATE systems, for example, hundreds of measurement pins are used to test each semiconductor wafer, with each pin requiring an individual ADC to reduce costly test time. The wires, switches and multiplexers used to connect the measurement pin to the measurement unit add cost, increase the risk of measurement errors and slow system response time. Also, the resulting heat dissipation is so great that data conversion must be moved from the test head to a separate mainframe. The exponentially lower power of the AD7980, relative to existing ADCs, allows designers to place the new devices adjacent to each measurement pin, simplifying the design and increasing overall system accuracy and throughput. This, in turn, reduces test time, which is a major cost component for users of ATE systems.

Improving Sensor Performance - Unlike competing devices, the power and size advantages of the AD7980 allow designers to incorporate the new ADC and a digital interface into analog sensor packages. This new breed of highly integrated 'smart sensors' eliminates the parasitic effects, signalling errors and delayed response time caused when the ADC is physically separated from the sensor using signal cables. In industrial sensing applications, this allows equipment operators to more easily and accurately measure changes in vibration, pressure and temperature that can degrade system operation.

"At National Instruments, we use ADI's PulSAR converters on a number of our core measurement and industrial I/O products," said Kurt Mandeville, principal hardware engineer at National Instruments Inc. "We see the AD7980 introduction extending PulSAR to a new level of combined high speed, low power, and small size, while preserving the performance we've come to expect from the PulSAR architecture."

The AD7980 PulSAR ADC features 7.5 mW power consumption at 1 MSPS and 75 microwatts at 10kSPS-the lowest power of any 16-bit ADC at any sample rate. Other performance enhancements include 2-LSB maximum INL and 91.5-dB signal-to-noise ratio (SNR) at 20 kHz. The AD7980 is available in LFCSP/QFN (lead-frame chip-scale package/quad flat no-lead) and MSOP (mini small-outline plastic) packages that, respectively, are five and three times smaller than any competing ADC packages. The AD7980 is pin-compatible with the AD768x MSOP family of 16-bit PulSAR ADCs, for designers looking to upgrade to a 1MSPS sample rate, and is compatible with Analog Devices' ADA4841 driver and buffer op-amps and ADR42x, ADR43x and ADR44x voltage references.


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