ADF41020 Microwave PLL Synthesizer

The ADF41020 frequency synthesizer from ADI's can be used to implement local oscillators as high as 18 GHz in the up conversion and down conversion sections of wireless receivers and transmitters. It consists of a low noise, digital phase-frequency detector (PFD), a precision charge pump, a programmable reference divider, and high frequency programmable feedback dividers (A, B, and P). A complete phase-locked loop (PLL) can be implemented if the synthesizer is used with an external loop filter and voltage controlled oscillator (VCO). The synthesizer can be used to drive external microwave VCOs via an active loop filter. Very high bandwidth means a frequency doubler stage can be eliminated, simplifying system architecture and reducing cost. The ADF41020 is software-compatible with the existing ADF4106/ADF4107/ADF4108 family of devices from ADI. Their pinouts match very closely with the exception of the ADF41020’s single-ended RF input pin, meaning only a minor layout change is required when updating current designs.