LMK04832EVM: abnormal CLK waveform

Alan Ke

Part Number: LMK04832EVM
Other Parts Discussed in Thread: LMK04832,

Hi,

We're currently testing LMK04832 EVM using default configuration.
We found that there is larege difference about waveform between 122.88 MHz and 61.44MHz.(showed as below)

(Left :122.88MHz, Right :61.44MHz)

Is it normal or is there any clock format need to be set?
Hoping that we can get a 50% duty cycle CLK from output.

Thank you!
Best reagrds,
Alan

over 2 years ago

0 Ajeet Pal over 2 years ago

TI__Genius 12550 points

Hi Alan,

LMK04832EVM's clock output ports are HW configured (terminations) for different output format, like CLKout0 to 3 are for LVPECL and others for different config. Please see the LMK04832EVM user guide (https://www.ti.com/lit/ug/snau215a/snau215a.pdf)

LMK04832 should give the 50% duty cycle output with default configuration, if you have measured at the same port.

Regards,

Ajeet Pal

0 Alan Ke over 2 years ago in reply to Ajeet Pal

Prodigy 70 points

Hi Ajeet,

The waveform figure showed above were measured at the same output ,
which means that they are using same HW configuration and same clk format.
The only difference are frequency but the waveform are much difference.
So we were wondering that is it normal or not?

Thank you!
Best reagrds,
Alan

0 Ajeet Pal over 2 years ago in reply to Alan Ke

TI__Genius 12550 points

Hi Alan,

While changing the frequency it's just changing the divider value and those are integer dividers so not give any duty cycle issue.

I would be suspecting the measuring probe those need to be check.

Regards,

Ajeet Pal

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LMK04832EVM: abnormal CLK waveform