PLL devices target RF & microwave communications designers

3rd June 2014

Analog Devices

Staff Reporter

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Three phase-locked loop (PLL) devices have been launched with one featuring, the company Analog Devices claim, the industry’s widest frequency coverage and lowest VCO phase noise in a single device. The ADF5355 PLL covers a 55 MHz to 14 GHz frequency spectrum, while the ADF4355-2 PLL features a 55 MHz to 4.4 GHz frequency span. Both devices are targeted at RF and microwave communications systems designers who need a single, high-performance wideband synthesizer.

Both PLLs integrate ultra-low-phase-noise VCOs that deliver -133 dBc/Hz @ 1 MHz offset at 6 GHz—at least 2 dB lower noise performance than any competing device. ADI have also introduced the ADF4155, an 8 GHz stand-alone fractional-N PLL. Together, the devices provide designers with several options for replacing discrete, high-frequency, higher-power PLLs and VCOs in demanding, ultra-wideband applications including cellular base stations, microwave point-to-point communications links, radar systems and test and measurement equipment.

These new PLLs are all supported on the latest version of the ADIsimPLL design tool, version 3.6, which is a free-to-download software tool that facilitates PLL/synthesizer designers in getting the best performance from ADI’s leading portfolio of PLL solutions.

The superior VCO phase-noise performance of the ADF5355 and ADF4355-2 is achieved through novel VCO topologies and architectures which were developed in conjunction with ADI’s new proprietary advanced SiGe processes. In ultra-wideband RF and microwave communications applications, this ultra-low phase noise has the benefit of improving overall system error rates and increasing data throughput to deliver better noise immunity and wider range.

ADI’s new, cost-effective, ultra-wideband PLL synthesizer ICs also feature up to 125 MHz phase comparator frequency and 38-bit resolution, which lowers jitter and allows for very fine step sizes, while the integrated PLL and VCO on an advanced BiCMOS process significantly reduces package size and power consumption compared to discrete GaAs implementations. And because a single PLL can be configured to operate from 55 MHz to 14 GHz, designers can more quickly reconfigure their system designs and reduce their parts inventory while still supporting multiple frequency bands.

The PLLs are well suited for designs that incorporate other ADI RF components, including the ADL5801 active mixer, ADL5375 broadband quadrature modulator and ADL5380 broadband quadrature I-Q demodulator, as a local-oscillator source for the AD9361 RF Agile Transceiver and as a clock source for the AD9625 12-bit, 2-GSPS A/D converter.