LMH1983 - TOF1 Alignment behavior

Kawai

Guru 19775 points

Other Parts Discussed in Thread: LMH1983

Hi Team,

Please let me ask you about LMH1983 TOF1 alignment function of Sync Near/Far/Slew.

As I confirmed the behavior, the result was different from the datasheet.

Please find attached the file I had summarized the test result.

When I set the Alignment mode to Always Align or Auto Align, phase relation of TOF1 and FIN were always almost the same with the waveform in slide 1.

Could you please give me explanation why the EVM is not operating the way it is set ?

Best Regards,
Kawai

LMH1983 TOF Alignment(ENG).pdf

over 9 years ago

0 Alan O over 9 years ago

TI__Mastermind 32575 points

Kawai-san,

I have notified the responsible BU engineer to address your inquiry.

Regards,
Alan

0 Nasser Mohammadi over 9 years ago in reply to Alan O

TI__Guru* 88905 points

Hi Kawai-San,

TOF1_Sync_Near and TOF1_Sync_Far have 4 combinations. These are as follows:

TOF1_Sync_Near TOF1_Sync_Far:

00 = Always Drift Lock

01 = Drift if we are < (2** LOA)X27MHz Clocks

Crash Lock if we are > (2** LOA)X27MHz Clocks

1X = Crash Lock

We are in process of changing the data sheet to reflect these.

Regards,,nasser

0 Kawai over 9 years ago in reply to Nasser Mohammadi

Guru 19775 points

Hi Nasser-san,

Thank you for the information.

In my evaluation with above "01" setting, it seems that the device had > (2** LOA)X27MHz Clocks.

Is this setting also applicable in Always Align Mode, or does it behave different ?

** I understand Always Align Mode is not recommended as it would increase jitter.

Best Regards,
Kawai

0 Dave Winder15947 over 9 years ago in reply to Nasser Mohammadi

Intellectual 485 points

Any ETA on that datasheet? Its 3 years old now.

More signal timing diagrams would be good too. Fout behavior is only shown for interlaced case relative to Fin. What is timing for progressive?

0 Nasser Mohammadi over 9 years ago in reply to Dave Winder15947

TI__Guru* 88905 points

Hi Dave,

We are including more timing diagrams and expect to have the data sheet out hopefully in three to four weeks. We are putting the data sheet in new format and add much more information.

Regards,,nasser

0 Michael Lu (Santa Clara) over 9 years ago in reply to Nasser Mohammadi

TI__Mastermind 29635 points

Hi Dave,

As of today, the latest datasheet revision (H) for the LMH1983 is on the web product folder.

Thanks,

Michael

0 Dave Winder15947 over 9 years ago in reply to Michael Lu (Santa Clara)

Intellectual 485 points

Very Cool. Thanks.

Clock & timing

Clock & timing forum

LMH1983 - TOF1 Alignment behavior