I am designing an ADC circuit for CCD, I am used ADC9822 and the circuit is exactly same as datasheet.
The sampling rate is 1.25MHz and ADC is programmed in single channel and CDS mode. The noise at the output is too much and I am losing 7 bits of the digital value. The attached file shows the digital output of the AD9822 while the analogue input is grounded.
Could you please help me to reduce the noise level in the output?
Also I need to mention that ARM cortex4 is used to generate required signals for ADC.
I think the only way you are going to get the noise under control is to go to a four layer board.
Could you please let me know what i need to do with two inside layers?
Do i need to connect both to ground or one to ground and the other VCC?
thanks for your help.
Thanks for your comment.
Could you please let me know how much resistance i need to add?
yes i did FFT on matlab but i did not get too much information but i will try one more time.
I have moved this discussion to Direct Digital Synthesis (DDS) community.