Hello,
We're using an ADS6443 A/D converter in one of our designs.
The Frame Clock frequency is 80 MHz and the Bit Clock frequency is 320 MHz DDR.
According to the datasheet, the Bit Clock should have a 90 degrees positive phase shift compared to the Frame Clock.
I.E: If the Bit Clock period is 3.125 nS ( 1 / 320 MHz ) - we're expecting its rising edge to arrive 0.78125 nS ( 3.125 nS / 4 ) after the rising edge of "Frame Clock".
But this isn't what we measure.
Instead, the rising edge of Bit Clock has a 180 degrees ( not 90 ) phase shift compared to the Frame Clock.
Could please advise this phenomenon, Thanks.
Note :
The point of measurement is directly on the output pins of the ADS6443.
Best regards,
Shai
