I have some test on ADF4107 these days and find some interesting things.
When ADF4107 locks well, I set any one of SPI port high - CLK, LE, SDI. Then power off ADF4107, the one of SPI is still high.
After a while, ADF4107 powered on, the PLL locks again in previous frequency. Seems the register part is powered on by the high level of SPI port.
When ADF4107 locks well, I pull down all SPI ports - CLK, LE, SDI. Then power off ADF4107, the SPI ports are all low of course.
After a while, ADF4107 powered on, the PLL doesn't lock. We need to re-write to ADF4107.
My doubt here is the internal registers of ADF4107 can be power by SPI port?