ADS5296A: ADCLK problem

Hi Zeev,

This issue could happen due to multiple reasons. Have you checked that the supply at each of the devices is reaching properly. There shouldn't be any drop in the supply reaching to each device. Have you also checked the same thing for SPI signals as well. Are they also reaching each device properly. Can you check SPI functionality is proper for each device by trying Power down register settings. Can you also make sure that the overall power dissipation is as expected. 

Hi,

1. The power supply look good.

2. SPI is function and I could write and read for each devise.

3. power dissipation is as expected.

I make counters in the FPGA to count the FCLK and see the problem before I make any SPI transection.

in the current card I have 3 units working properly and 5 with problems.

the digital supply is common and I have dc2dc of 4A which almost all the current is for the ADS5296A.

this is much more than the ADS5296A need. (I work with 8 channel at 30 MHZ)

The analog supply have LDO of 400ma which is much more than the ADS5296A need.

zeev gerber

Hi Zeev,

Thanks for sharing these details. Can you please share more details like board schematic, register settings of the device and the sampling rate. Is this a new board design which you are testing for the first time? Or is it specific to only the board under test?

Since this is a public forum, please feel free to reach out to us on support_us_afe_tx@list.ti.com for sensitive information. 

How to attach the board schematic? do you have drop box or similar? I could also send the board schematic to you email if you send it to me.

sampling rate is 30Mhz.

why you need the register settings? after reset I should see the adclk.