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

The AD9911 is the first DDS to incorporate SpurKillertechnology and multitone generation capability. Multitonemode enables the generation up to four concurrent carriers;frequency, phase and amplitude can be independentlyprogrammed. Multitone generation can be used for systemtests, such as inter-modulation distortion and receiver blockersensitivity. SpurKilling enables customers to improve SFDRperformance by reducing the magnitude of harmoniccomponents and/or the aliases of those harmonic components.

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

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

The DDS acts as a high resolution frequency divider with theREF_CLK as the input and the DAC providing the output. TheREF_CLK input can be driven directly or used in combinationwith an integrated REF_CLK multiplier (PLL). The REF_CLKinput also features an oscillator circuit to support an externalcrystal as the REF_CLK source. The crystal can be used incombination with the REF_CLK multiplier.The AD9911 I/O port offers multiple configurations to providesignificant flexibility. The I/O port offers an SPI-compatiblemode of operation that is virtually identical to the SPI operationfound in earlier Analog Devices DDS products.

Flexibility is provided by four data pins (Pin SDIO_0,Pin SDIO_1, Pin SDIO_2, and Pin SDIO_3) that allow fourprogrammable modes of I/O operation.The DAC output is supply referenced and must be terminatedinto AVDD by a resistor and an AVDD center-tapped transformer.The DAC has its own programmable reference to enabledifferent full-scale currents.

The DDS core (the AVDD pins and the DVDD pins) is poweredby a 1.8 V supply. The digital I/O interface (SPI) operates at3.3 V and requires that the Pin DVDD_I/O (Pin 49) beconnected 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

This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.