RF Synthesizer Integrates DDS and PLL Functions

Direct digital synthesis (DDS) and phased locked loop (PLL) capabilities are built into the AD9956 AgileRF synthesizer for low-power applications in marine, military, radar and satellite communications systems. The DDS component uses a 14-Bit DAC operating at up to 400 Msamples/s and an advanced phase detector plus charge pump combination that, when configured with an external voltage-controlled oscillator, enables synthesis of digitally programmable, frequency agile analog-output sinusoidal waveforms at up to 2.7 GHz. The PLL circuitry includes a phase detector with scalable 200-MHz inputs and digital control over the charge pump current range. A unique feature is the device’s reportedly narrow linear frequency sweep that allows radar systems to use the principle of pulse compression. In turn, highly linearized radar sweeps result from the generation of a precision clock for the DDS. The synthesizer also provides fast frequency hopping and fine tuning resolutions through a 48-Bit frequency tuning word. The synthesizer is available in a 48-lead, lead form chip scale package (LFCSP) with an extended operational temperature range from -40°C to +125°C. Pricing is $17.25 each/1,000. For further information and availability, contact ANALOG DEVICES INC., Wilmington, MA. (800) 262-5643.