We have two AD9644 evaluation boards
The AD9644-80 board is working OK.
The AD9644-155 board clock oscillator Y502 was found to be oscillating at 26.7 MHz, not 80 MHz as expected.
When digging into the oscillator problem, it was found that 3P3V_ANALOG is at 2.0V.
The reason for this is, that R506 pulls low the internal regulator of the AD9524 - thus loading the 3P3V_ANALOG voltage.
In the AD9644-80 board, R506 is not assembled, and there is no problems.
In the AD9644-155 board R506 is assembled, shorting U501 pin 12 to ground via R508.
The problem can clearly be seen in the schematic 9644CE01, where R506 - R508 create a path to ground from the LDO output.
Are you aware of this problem ?
Are there other differences between these two board BOM versions ?
Can I have a correct schematic for the AD9644-80 board ?
Do you think the AD9524 on my board is now damaged ?
regards Miika K