500 MSPS Direct Digital Synthesizer with 10-Bit DAC

The AD9911 is a complete direct digital synthesizer (DDS). This device includes a high speed DAC with excellent wideband and narrowband spurious-free dynamic range (SFDR) as well as three auxiliary DDS cores without assigned digital-to-analog converters (DACs). These auxiliary channels are used for spur reduction, multitone generation, or test-tone modulation.

The AD9911 is the first DDS to incorporate SpurKiller technology and multitone generation capability. Multitone mode enables the generation up to four concurrent carriers; frequency, phase and amplitude can be independently programmed. Multitone generation can be used for system tests, such as inter-modulation distortion and receiver blocker sensitivity. SpurKilling enables customers to improve SFDR performance by reducing the magnitude of harmonic components and/or the aliases of those harmonic components.

Test-tone modulation efficiently enables sine wave modulation of amplitude on the output signal using one of the auxiliary DDS cores.

The AD9911 can perform modulation of frequency, phase, or amplitude (FSK, PSK, ASK). Modulation is implemented by storing profiles in the register bank and applying data to the profile pins. In addition, the AD9911 supports linear sweep of frequency, phase, or amplitude for applications such as radar and instrumentation.

The DDS acts as a high resolution frequency divider with the REFCLK as the input and the DAC providing the output. The REFCLK input can be driven directly or used in combination with an integrated REFCLK multiplier (PLL). The REFCLK input also features an oscillator circuit to support an external crystal as the REFCLK source. The crystal can be used in combination with the REFCLK multiplier. The AD9911 I/O port offers multiple configurations to provide significant flexibility. The I/O port offers an SPI-compatible mode of operation that is virtually identical to the SPI operation found in earlier Analog Devices DDS products.

Flexibility is provided by four data pins (Pin SDIO0, Pin SDIO1, Pin SDIO2, and Pin SDIO3) that allow four programmable modes of I/O operation. The DAC output is supply referenced and must be terminated into AVDD by a resistor and an AVDD center-tapped transformer. The DAC has its own programmable reference to enable different full-scale currents.

The DDS core (the AVDD pins and the DVDD pins) is powered by a 1.8 V supply. The digital I/O interface (SPI) operates at 3.3 V and requires that the Pin DVDDI/O (Pin 49) be connected to 3.3 V.

Applications

* Agile local oscillator

* Test and measurement equipment

* Commercial and amateur radio exciter

* Radar and sonar

* Test-tone generation

* Fast frequency hopping

* Clock generation

* Patented SpurKiller technology

* Multitone generation

* Test-tone modulation

* Up to 800 Mbps data throughput

* Matched latencies for frequency/phase/amplitude changes

* Linear frequency/phase/amplitude sweeping capability

* Up to 16 levels of FSK, PSK, ASK

* Programmable DAC full-scale current

* 32-bit frequency tuning resolution

* 14-bit phase offset resolution

* 10-bit output amplitude-scaling resolution

* Software-/hardware-controlled power-down

* Multiple device synchronization

* Selectable 4× to 20× REFCLK multiplier (PLL)

* Selectable REFCLK crystal oscillator

* 56-lead LFCSP