LMK01801: About the output clock edge

Bo Dong26

Part Number: LMK01801

Hi,

I am planning to use the LMK01801 to generate 100kHz clock signals with programmable delay with 25ps step, and I need the edges of the clock to be very sharp. From the datasheet, with LVPECL output, the Tr and Tf are 200ps, but I need the Tr and Tf to be around 25ps. Could you teach me a way to make the edge sharper?

Thank you in advance.

over 9 years ago

0 Timothy T over 9 years ago

TI__Mastermind 28590 points

I'm afraid we can't get the output to be 25 ps rise/fall 20% to 80%. The only way you could change Tr/Tf to be smaller is to redefine the thresholds of start/stop. For example typically we use 20% to 80%. Rise/fall would be faster if you defined measurement from 40% to 60% for example, but this probably doesn't help you.

73,
Timothy

0 Bo Dong26 over 9 years ago in reply to Timothy T

Prodigy 250 points

Hi Timothy,

Thank you so much for the reply. Are there any ICs to reshape the output pulses from the LMK01801 to make them sharper?

Thanks,

Timothy T said:
I'm afraid we can't get the output to be 25 ps rise/fall 20% to 80%. The only way you could change Tr/Tf to be smaller is to redefine the thresholds of start/stop. For example typically we use 20% to 80%. Rise/fall would be faster if you defined measurement from 40% to 60% for example, but this probably doesn't help you.

73,
Timothy

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LMK01801: About the output clock edge