How to clock 4 ADC07D1520s from a LMX2541

David J Schmidt

Other Parts Discussed in Thread: ADC07D1520, LMX2541, LMK01020, LMK04808

I need some help choosing the best solution for a 1:4 1,500 MHz clock distribution system, that will feed 4 ADC07D1520 chips. The 1,500MHz are generated by a LMX2541 from a 100MHz system clock.

What is the best method to drive the 4 converters from the LMX2541?

What circuitry is required to synchronize the LVDS outputs using this clocking solution?

over 8 years ago

0 Jim Brinkhurst1 over 8 years ago

TI__Mastermind 43930 points

Hi David

Sorry about the delay responding. The LMK01020 (LVPECL outputs) can provide 1:4 distribution of the LMX2541 output at 1.5 GHz. Another option would be using the LMK04808 operating at 3 GHz internally dividing down to 1.5 GHz for 4 outputs. This would eliminate the LMX2541 need. I would recommend using the LVPECL output mode for that device also. Use the recommended terminations for LVPECL output from those device datasheets, but remember that the CLK inputs to the ADC must be AC-coupled to ensure they are at the proper common mode voltage.

To synchronize the LVDS DCLK and DATA outputs you will need to use the differential DCLK_RST inputs and follow the procedure outlined in the datasheet and this document:

/cfs-file/__key/communityserver-discussions-components-files/73/2781.AB0610_2D00_RS_2D00_JB-_2D00_-Synchronizing-multiple-ADCs-July-2010.pdf

Regards,

JIm B

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How to clock 4 ADC07D1520s from a LMX2541