1 GSPS Direct Digital Synthesizer

The AD9858 is a direct digital synthesizer (DDS) featuring a 10-bit digital-to-analog converter (DAC) operating up to 1 GSPS. The AD9858 uses advanced DDS technology coupled with an internal high speed, high performance DAC to form a digitally programmable, complete high frequency synthesizer capable of generating a frequency-agile analog output sine wave at up to 400 MHz. The AD9858 is designed to provide fast frequency hopping and fine tuning resolution (32-bit frequency tuning word). The frequency tuning and control words are loaded into the AD9858 via parallel (8-bit) or serial loading formats. The AD9858 contains an integrated charge pump (CP) and phase frequency detector (PFD) for synthesis applications requiring the combination of a high speed DDS along with phase-locked loop (PLL) functions. An analog mixer is also provided on chip for applications requiring the combination of a DDS, PLL, and mixer, such as frequency translation loops and tuners. The AD9858 also features a divide-by-2 on the clock input, allowing the external reference clock to be as high as 2 GHz.

The AD9858 is specified to operate over the extended industrial temperature range of –40°C to +85°C.

Applications

* VHF/UHF LO synthesis

* Tuners

* Instrumentation

* Agile clock synthesis

* Cellular base station hopping synthesizers

* Radars

* SONET/SDH clock synthesis

Data Sheet, Rev. C, 2/08

* 1 GSPS internal clock speed * Up to 2 GHz input clock (selectable divide-by-2) * Integrated 10-bit DAC * Excellent phase noise and SFDR * 32-bit programmable frequency register * Simplified 8-bit parallel and SPI serial control interface