DDS ICs from Analog Devices with integrated 14-bit DACs offer improved dynamic performance

The AD9910 and AD9957 are the first DDS devices to achieve speeds of 1 giga samples per second (GSPS), while lowering power consumption by more than 50 percent, ensuring the DDS ICs meet the requirements of a broad range of communications, instrumentation and defense applications.

The 1 GSPS operating speed combined with the 14-bit DAC resolution of the AD9910 DDS allows communications, defense and instrumentation system engineers to improve dynamic performance for output frequencies to 400 megahertz (MHz). For wireless and wired systems, the AD9957 DDS modulator or quadrature digital upconverter (QDUC) simplifies data transmission by offering real outputs up to intermediate frequencies of 400 MHz.

Increasing clock speeds to 1 GSPS on high-resolution DDS ICs allows our customers to generate higher output frequencies with improved dynamic performance, said Kevin Kattmann, product line director, High Speed Signal Processing Group, Analog Devices. The new DDS products represent a
significant step forward, providing 8 to 12 dB better spurious free dynamic range (SFDR) when compared to previous generations. By improving SFDR and reducing the DDS core power consumption, ADI continues to expand the number of markets that can take advantage of digital synthesis solutions.

The AD9910 and AD9957 are the first devices developed on a new, low-power DDS core that consumes only one-tenth the power of previous generation cores. Patented technology licensed from Pentomics, a California-based company that specializes in circuit design and signal processing for digital
communications, was instrumental in helping reduce core power consumption.

DDS circuit designers at ADI utilized Pentomics' Star DDS Designer® software and Star DDS Analyzer® software tools in the design and analysis of DDS cores to help ensure the most efficient DDS chip design for a given application. In conjunction with these software tools, ADI has also licensed
A System for Analysis and Design of Direct Digital Frequency Synthesizers and Method and Apparatus for Improved Direct Digital Frequency Synthesizer patents from Pentomics.

Featuring a 16-bit parallel port with update rates to 250 MHz, the AD9910 digital synthesizer allows designers to update a 32-bit frequency tuning word every 8 ns. This fast programming capability benefits applications requiring extremely fast changes in frequency or phase, such as high-speed
waveform generators, frequency hopping synthesizers, secure communications, and a variety of radar and scanning systems. The AD9910's 14-bit DAC resolution and 1 GSPS clock rate translate into improved SFDR and phase noise performance across all these applications.

In addition, the AD9910 offers a 70 percent reduction in power dissipation when compared to existing solutions, consuming just 700 milliwatts at full operating speed. The enhanced on-chip reference clock multiplier reduces system cost by generating the internal 1 GSPS clock from a low frequency,
low cost external source. Additional features added to the DDS core include: a secondary accumulator for linear sweeping of frequency, phase or amplitude; RAM for user defined non-linear sweeping; and circuitry easing synchronization if multiple devices are needed in a single system.

The newest member of ADI's portfolio of DDS devices, the AD9910 may be combined with the new ADCMP60x comparators or AD951x clock dividers, to generate programmable high-speed, low-jitter clock solutions. ADI's ADIsimDDST online evaluation tool assists users in selecting, evaluating and
troubleshooting ADI's DDS ICs. Designed with flexibility in mind for a broad range of applications, the AD9910 is priced at $35 per unit in 1,000-piece quantities.


The AD9957 QDUC integrates a high-speed DDS, a 14-bit DAC, clock multiplier circuitry and digital filters on a single chip, enabling uncomplicated, cost-effective baseband up-conversion for data transmission in wired or wireless communications infrastructure systems, including WiMAX
applications. The QDUC achieves greater than 50 percent power reduction (~1.3 W at 1 GSPS) over existing QDUCs and operates by receiving an interleaved I/Q data stream, interpolating it, and synthesizing the desired signal for transmission when clocked at the same rate. The 1 GSPS
numerically controlled oscillator (NCO) and DAC allow the AD9957 to provide direct outputs up to 400 MHz, eliminating some up-conversion stages and enabling less stringent filter requirements.

The low-noise, on-chip reference clock multiplier allows for the use of low cost, low frequency sources for the system clock, while still delivering excellent dynamic performance. The AD9957 also supports test vectors, and amplitude ramping capability. The latest addition to ADI's family of DDS
modulators, the AD9957 QDUC together with ADI's portfolio of TxDAC+® transmit digital-to-analog converters, offers wireless infrastructure systems engineers a wide range of solutions for transmit path designs. The user interface to the control functions of the AD9957 includes a serial port
easily configured to work with ADI's Blackfin processors. The AD9957, which is optimized for communications applications, is priced at $21 per unit in 1,000-piece quantities.