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wirelessZONE Products for the week of December 10, 2007
Analog Devices Says…
AD9913: DDS Technology Now Available for Low-Power Portables
Consuming just 50 mW of power at a 250-MHz clock rate IC delivers price and performance to mobile industrial and communications devices
Analog Devices, Inc., a global leader in high-performance semiconductors for signal processing applications, is expanding the applicability of its industry leading direct digital synthesis technology into battery-powered industrial, communications and defense electronics applications with the introduction of a complete low-power, low-cost Direct Digital Synthesizer (DDS) specifically designed for wireless, handheld equipment. Unlike competing approaches used to synthesize a digitally controlled frequency, the AD9913 is the first DDS device to deliver a 250-MHz clock rate while consuming as little as 50 mW of power. At less than $5 in volume quantities and available in a compact chip-scale package, the new IC is ideally suited for portable barcode scanners, radar detectors, remote radio controls and other products that require a cost-effective combination of performance and low-power operation.
Unlike phase-locked loop (PLL) devices, which suffer from settling times measured in microseconds and fine-tuning limitations, the AD9913 settles in nanoseconds with granularity well below 10 mHz. Other approaches, including field-programmable gate arrays (FPGAs) with embedded DDS functions, have difficulty matching the AD9913’s greater than 80-dB spurious-free dynamic range (SFDR) performance on a 100-MHz output signal while requiring higher operating power and the addition of a discrete digital-to-analog converter (DAC) to synthesize the sine wave. The AD9913 includes an on-chip 10-bit high-speed DAC with no price premium compared to a stand-alone DAC. The fine-tuning granularity and higher SFDR of the AD9913 allow it to more quickly and accurately generate a stable signal in the band of interest. In a remote radio-controlled application, for example, such as an unmanned aircraft, this means the operator is less likely to lose contact with the airplane due to frequency interference that can result in a dropped signal.
“Larger systems like wireless base stations and test and measurement equipment have been taking advantage of the higher operating-frequency ranges, faster linear frequency hopping and other performance benefits of DDS technology for the better part of a decade,” said Kevin Kattmann, product line director of High-Speed Signal Processing, Analog Devices. “With the launch of the AD9913, designers of battery-powered devices can now incorporate the same faster switching speeds, fine frequency resolutions and broader frequency spectrum into their products with no price or power penalty.”
EN-Genius Says…
This is just the second 1.8 V single rail 10-bit DAC resolution DDS from Analog Devices. The differences from the first, the AD9911, are the reduction of the master clock frequency to 250 MHz (from 500 MHz), shaving 10 mA off the quiescent, a reduced compliance range of 0.8 V (from 1.8 V) and the addition of parallel programming capability as well as the serial. The AD9913 has also been squeezed into LFCSP-32 intsead of a LFCSP-56.
The AD9913 has a full-scale output current from the DAC of 4.6 mA with a maxmum INL of ±0.5 LSB and a DNL of ±0.4 LSB. The output can be a frequency-agile analog sinusoidal signal of up to 100 MHz with a resolution better than 0.058 Hz and 0.022° phase tuning resolution. The signal can deploy frequency hopping, phase modulation, and there is also a user-defined linear sweep mode. There are 8 frequency or phase offset profiles. Many sections of the part can be powered down when they are not being used. Both software and hardware power-downs can be used.
Control is from words loaded through either the serial or parallel ports. The maximum parallel clock frequency is 32 MHz with a maximum of 33 MHz on the serial.
The low power and size of the AD9913 make it an ideal choice for portable equipment, such as portable spectrum analyzers, but it can be used as the local oscillator in any transmit/receive chain or as a programmable clock generator. It will do well.
The AD913 is in production in LFCSP-32 and is priced at $9.65 in 1000-piece lots and $4.65 in 100-k piece lots.
Data Sheet
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