Can the ADF5709 VCO be controlled with a fast DAC, such as the AD3551R, for stable frequency control within the 10-16 GHz range, and achieve a 200 ns setting time?

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You can certainly drive a VCO open loop with a DC voltage or a ramping voltage if you want to make a chirp. The ADF5709's frequency stability vs temperature appears to be quite good, with minimal variation between hot, cold, and ambient conditions. However, there will be some part-to-part variation, meaning that the same input voltage may not yield the exact same frequency across different VCO units. So you should include calibration in your system to account for this variation. The phase noise performance should match what is specified in the datasheet (Figure 12), but any noise on the DAC output voltage will degrade this performance and slightly modulate the output frequency. The shape of the phase noise will resemble Figure 12 rather than the classic PLL phase noise curve. The settling time of the VCO when controlled by a fast DAC will be much faster than that of a PLL/VCO circuit, which may be advantageous depending on your application.

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Can the ADF5709 VCO be controlled with a fast DAC, such as the AD3551R, for stable frequency control within the 10-16 GHz range, and achieve a 200 ns setting time?