DAC38J82: The dac38J82 output contains other unwanted waveforms.

user4428069

Part Number: DAC38J82
Other Parts Discussed in Thread: , LMK04828

The dac38J82 output contains other unwanted waveforms.

For example, when you want to output 70M, but also output unwanted 30M, 50M, 90M, 110M, 130M and so on, I found that they are added 20M。

I just output 70M in the spectrogram, but there are many other waveforms. LMFS：4211 400Msps

over 5 years ago

0 dBrock over 5 years ago

TI__Genius 12780 points

Hello,

We are taking a closer look, and will be back with you soon.

Have you tried using the NCO at 70 MHz, or is this output generated from a pattern file?

Best Regards,

Dan

0 jim s over 5 years ago in reply to dBrock

TI__Guru* 91947 points

DAC38J82_EXT_CLK_400M.pptx DAC38J82_4211_Fs_400M_K_20.cfgUser,

It appears you have some issues with either register settings, data test pattern, or your clock source. Attached is a setup used to re-create your test with the TI DAC38J82EVM and a TSW14J56EVM. I also attached the configuration used by the DAC and LMK04828 that is on the EVM.

Regards,

Jim

0 user4428069 over 5 years ago in reply to dBrock

Prodigy 160 points

I useing output generated from a pattern file ，But this happens when you use NCO

0 user4428069 over 5 years ago in reply to jim s

Prodigy 160 points

There is still this trouble.Please help me

My schematic diagram is designed in this way.

0 user4428069 over 5 years ago in reply to jim s

Prodigy 160 points

Please help me to solve these problems！！

please help me!!

0 jim s over 5 years ago in reply to user4428069

TI__Guru* 91947 points

User,

Based on your comments (I useing output generated from a pattern file ，But this happens when you use NCO), I am guessing you are attempting to use the DAC NCO along with the data pattern file from the FPGA, correct? If so, are you having any issues with the NCO turned off? Can you send your complete DAC and LMK register settings?

Regards,

Jim

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DAC38J82: The dac38J82 output contains other unwanted waveforms.