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AD9689 ADC data is noisy after initialization

Question asked by fuji38 on Feb 9, 2018
Latest reply on Apr 18, 2018 by UmeshJ

Hi, I am developing a waveform acquisition system using AD9689-2600EBZ and a FPGA board. Succeeded in capturing ADC data at 2 GS/s over JESD204B. Basically it works. But the ADC data looks noisy for a while after initialization of AD9689 registers. Noise level decreases with time, and disappears after a minute. See attached picture.

It depends on initialization of the registers, not power cycle. Instead of ADC data, I tried out generating ramp data in test mode of AD9689 (register 0x0550). There are no noises in that case. So the noise seems to come from the ADC core.

 

I am thinking about waiting for 2 minutes, like a warm-up time.

 

Any ideas to eliminate the warm-up time?

 

Thanks,
--fuji

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