ADC34J45: Test Pattern Discrepancy

Hi Aaron,

Do you have the original post you can forward to me please and I can check into this?

Thanks,

Rob

Rob, 

Here is the original post I am referencing: https://e2e.ti.com/support/data-converters-group/data-converters/f/data-converters-forum/653912/adc34j45-test-pattern-not-working-well

To add some context, I am now running into a similar finding. Here are the ADC34J45 test pattern discrepancies I've identified:

1. Deskew pattern 0x2AAA, instead of 0x3AAA
2. 8-point sine:

   datasheet	0	2399	8192	13984	16383	13984	8192	2399
   actual	2654	4276	8192	12107	13729	12107	8192	4276

3. SerDes Outputs clock pattern 0xB5B5, instead of 0xAAAA

Thanks,

Aaron

Aaron,

I think this is an error in the data sheet. We are checking with the design team regarding this. I did notice the deskew pattern was 0x2AAA but the 8-point sine wave I observed was different from what you are reporting. See attached captured results. The values I am seeing are 0, 12468, 10846, 12468, 0, 3915, 9633, 3915.

I also noticed in the data sheet the bits used for setting the test pattern modes are wrong in registers 0x0A and 0x0B.

Bits 7:4 of register 0x0A is used to set the pattern for CHA and bits 3:0 are used to set the pattern for CHB. Bits 7:4 of register 0x0B is used to set the pattern for CHC and bits 3:0 are used to set the pattern for CHD.

Regards,

Jim

8_pt_sinewave.pptx