ADF4368 Microwave Wideband Synthesizer with Integrated VCO

ADI's ADF4368 is a high-performance, ultra-low jitter, integer-N and fractional-N phase-locked loop (PLL) with integrated VCO ideally suited for frequency conversion applications.

The high-performance PLL has a figure of merit of -239 dBc/Hz, very low 1/f noise of normalized -287 dBc/Hz, and high PFD frequency that can achieve ultra-low in-band noise and integrated jitter. The ADF4368 can generate any frequency from 800 MHz to 12.8 GHz without an internal doubler, eliminating the need for sub-harmonic filters. The Σ-Δ modulator includes a 25-bit fixed modulus that allows hertz frequency resolution and an additional 17-bit variable modulus, which allows even finer resolution and flexibility for frequency planning. The 9 dBm output power at 12.8 GHz in single-ended configuration with 16-step power adjust feature makes it very useful for any application.

For multiple frequency conversion applications, such as phase array radar or massive MIMO systems, the outputs of multiple ADF4368 can be aligned using the SYNC input or EZSync™. The EZSync method is used when it is difficult to precisely distribute the SYNC signal to all devices. For applications that require deterministic delay or delay adjustment capability, a programmable reference to output delay with <1 ps resolution is provided. The reference to output delay is guaranteed across multiple devices and temperatures, allowing for predictable and precise multichip alignment.

The simplicity of the ADF4368 block diagram eases development time with a simplified serial peripheral interface (SPI) register map, external SYNC input, and repeatable multichip phase alignment both in integer mode and fractional mode.

The EV-ADF4368SD1Z evaluates the performance of the ADF4368 fractional frequency synthesizer with an integrated voltage-controlled oscillator (VCO) for phase-locked loops (PLLs). A photograph of the EV-ADF4368SD1Z is shown in Figure 1 of the user guide. The EV-ADF4368SD1Z contains the ADF4368 frequency synthesizer with an integrated VCO, a USB interface, power supply connectors, on-board reference oscillator, propagation delay calibration paths, and Subminiature Version A (SMA) connectors. The outputs are AC-coupled with 50 Ω transmission lines making the outputs suitable to drive 50 Ω impedance instruments. The EV-ADF4368SD1Z requires an SDP-S board (not supplied with the kit). The SDP-S allows software programming of the EV-ADF4368SD1Z with ACE software.