The AD9956 is Analog Devices’ newest AgileRF synthesizer. The device is comprised of DDS and PLL circuitry. The DDS features a 14-bit DAC operating at up to 400 MSPS and a 48-bit frequency tuning word (FTW). The PLL circuitry includes a phase frequency detector with scaleable 200 MHz inputs (divider inputs operate up to 655 MHz) and digital control over the charge pump current. The device also includes a 655 MHz CML-mode PECL-compliant driver with programmable slew rates. The AD9956 uses advanced DDS technology, an internal high speed, high performance DAC, and an advanced phase frequency detector/charge pump combination, which, when used with an external VCO, enables the synthesis of digitally programmable, frequency-agile analog output sinusoidal wave-forms up to 2.7 GHz. The AD9956 is designed to provide fast frequency hopping and fine tuning resolution (48-bit frequency tuning word). Information is loaded into the AD9956 via a serial I/O port that has a device write-speed of 25 Mb/s. The AD9956 DDS block also supports a user-defined linear sweep mode of operation.
The AD9956 is specified to operate over the extended automotive range of ?40°C to +125°C.