HMC778 How to mute output signal and force LD low?

HMC778 after powerup (without registers programming) working on maximum VCO Output Frequency (about 10.9 GHz) and LD is unstable: sometimes LD=1 or LD=0, or fastly switching between 1 and 0.

How to disable output and force LD=0 (in other words: how to disable VCO and PLL)?

I tried writing 0x000000 to Reg 0x01 - no way
also tried writing 0x000000 to Reg 0x08 - no effect

i work in HMC mode SPI and CE pin is permanently high (can't control)