2.7 GHz DDS-Based AgileRF™ Synthesizer

The AD9956 is Analog Devices’s first AgileRF synthesizer. The device is comprised of a DDS and PLL circuitry. The DDS features a 14-bit DAC operating up to 400 MSPS and a 48-bit frequency tuning word. The PLL Circuitry includes a phase detector with scaleable 200 MHz inputs (pre-scalar inputs operate up to 650 MHz) and digital control over the charge pump current. The device also includes a 650 MHz PECL driver with programmable slew rates.The AD9956 uses advanced DDS technology, an internal high-speed, high performance D/A converter and an advance phase-detector/charge pump combination to enable the synthesis of digitally-programmable, frequency-agile analog output sinusoidal waveforms 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 which has a device write speed of 25 MBit/sec. 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.

Applications

* Agile LO frequency synthesis

* FM chirp source for radar and scanning systems

* Automotive radars

* Test and measurement equipment

* Acousto-optic device drivers

* 400 MSPS Internal DDS Clock Speed

* 48-bit frequency tuning word

* 14-bit Programmable Phase Offset

* Integrated 14-bit DAC

* Excellent Dynamic Performance

* Phase noise ≤ 135 dBc/Hz @ 1 KHz offset

* −80 dB SFDR @ 160 MHz (±100 KHz offset IOUT)

* 25 Mb/s write-speed serial I/O control

* 655 MHz programmable input dividers for the phase

* frequency detector (÷M, ÷N) {M, N = 1..16} (bypassable)

* Programmable RF divider (÷R) {R = 1, 2, 4, 8} (bypassable)