I have problems with communicating with the AD9252 via SPI. I try to write 0x01 to reg 0x08 and 0x01 to reg 0xFF to switch AD9252 in PowerDown and looking at power consumption. I noticed reducing power consumption (and increse after writing 0x00 reg 0x08 and 0x01 to reg 0xFF) in only few attempts, but majority of attempts doesn't take effect. After sending a read command AD9252 doesn't answer and doesn't switch SDIO in output mode at all.
SPI: speed - about 2khz, MSB first, CS always 0, data valid on rising edge of CLK. Levels of SDIO, CLK is 3.3V (SDIO line have 1k resistor).
Main clock of ADC is 50 Mhz, LVDS. Data on digital outputs are present.
I will be grateful for any help or advice.
Below is oscillograms(writing 0x01 to reg 0x08 on left screenshot and writing 0x01 to reg 0xFF on right) and schematic:
Sorry for poor english.