LMX2820: Integer boundary Spurious data

Pathamuthu K

Part Number: LMX2820
Other Parts Discussed in Thread: PLLATINUMSIM-SW,

Hi,

Integer boundary spur frequency & its level not mentioned in datasheet, Can you please tell exactly what are all the spurs will arise & its level with respect to the carrier (particularly any KHz spur).

In simulation I saw Phase detector frequency spurs & its level, but i need data for integer boundary spurs in KHz offset.

Output frequency: 9 to 14.7GHz

Input Reference frequency: 100MHz

over 4 years ago

0 Vibhu Vanjari over 4 years ago

TI__Genius 11900 points

Hello Pathamuthu,

PLLATINUMSIM-SW will give you the level of the integer boundary spurs as well. Using the tool is the best way to check for spurs. You will need to check for each output frequency separately as the levels will change between 9 GHz and 14.7 GHz. Another thing to note is that currently pre-production LMX2820 samples are available, we are testing final silicon and the spur simulations will be updated in the next month or two.

If you have a particular frequency you would like our help simulating we can help with that. Please let us know.

Thanks,

Vibhu

0 Pathamuthu K over 4 years ago in reply to Vibhu Vanjari

Prodigy 100 points

Hi Vibhu Vanjari,

Could you please test and share the phase noise (Raw data) & spectrum waveforms with span 100KHz & 1MHz to check integer boundary spur level for the frequency 14650MHz with 100MHz reference.

0 Vibhu Vanjari over 4 years ago in reply to Pathamuthu K

TI__Genius 11900 points

Hello Pathamuthu,

I can take this measurement next week. I will share the data once I have it.

Thanks,

Vibhu

0 Vibhu Vanjari over 4 years ago in reply to Vibhu Vanjari

TI__Genius 11900 points

Hello Pathamuthu,

Please see the attached spreadsheet containing the measurements.

Note that the phase noise can be further improved with a cleaner reference frequency. I used the SMA100A to generate a 100 MHz input. The E5052A cannot measure phase noise above 7 GHz, so I used the same VCO frequency with a channel divider of 2 to take the phase noise measurement.

Thanks,

Vibhu

7318.LMX2820 e2e 948707.xlsx

0 Pathamuthu K over 4 years ago in reply to Vibhu Vanjari

Prodigy 100 points

Hi Vibhu,

Thanks for your quick response,

Our spurious rejection requirement is <-75dBc with span 100KHz. From the test results provided by you, we cannot able to check its level. Some noise raised at around 40KHz offset in the test results.

So please check with min 80dB as signal to noise ratio.

0 Noel Fung over 4 years ago in reply to Pathamuthu K

TI__Guru** 106720 points

Hi Pathamuthu,

Most of the team member are on Thanksgiving holidays, response will be a bit slow. We may not be able to provide test data until next week.

0 Pathamuthu K over 4 years ago in reply to Noel Fung

Prodigy 100 points

Hi Noel,

Please provide the data after Thanks giving holidays.

0 Vibhu Vanjari over 4 years ago in reply to Pathamuthu K

TI__Genius 11900 points

Hello Pathamuthu,

I appreciate your patience I can take this measurement next week or the week after.

Thanks,

Vibhu

0 Vibhu Vanjari over 4 years ago in reply to Vibhu Vanjari

TI__Genius 11900 points

Hello Pathamuthu,

I will send you the results via email when I have the data. I am closing this e2e thread but please feel free to continue the conversation via email. I have already sent you an email.

Thanks,

Vibhu

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LMX2820: Integer boundary Spurious data