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can i use the CDCM7005 as a 1:10 lvcmos buffer

guoqing xu
Prodigy 50 points
Other Parts Discussed in Thread: CDC7005, CDCM7005, CDCE62005, CDCM7005-SP

Hello Team,

i found an article about cdc7005 in the application report:

   Using the CDC7005 as a 1:5 PECL Buffer With a
Programmable Divider Ratio on Each Output (SCAA060B)

i want to know can i use  the CDCM7005 as a 1:10 lvcmos buffer With a programmable divider ratio on each output .just like use cdc7005

.That means input a dedicated frequence Lvpecl clock to the pin VCXO_in&VCXO_inB  and  get 10 ways output clock.

  • 0
    TI__Mastermind 24205 points

    Hi,

    CDCM7005 does not have individual dividers on the outputs. Do you require 10 independent dividers for the 10 LVCMOS outputs?

    Regards

    Arvind Sridhar

  • 0
    TI__Genius 10320 points

    Hi Guoqing,

    As Arvind mentioned, the CDCM7005 does not feature individual output dividers. A device that may meet your requirements is the CDCE62005 in bypass mode. This device features EEPROM so programming after power up is not necessary, but dividers are paired per driver - there are 5 possible pairs of divide values.

    Gabe

  • 0 in reply to Arvind Sridhar
    Prodigy 50 points

    hi，Arvind Sridhar

    no，i need distribute 1 clock to 10 ad devices and all the distributed clocks must have  the same frequence and phase.

      thanks a lot

  • 0 in reply to Gabe Ayala
    Prodigy 50 points
    hi gabe
    I didnot need the individual outputs, i only need copy the input clock and distribute the clock to ten outputs, in one word ,i use the cdcd7005 just as a clock tree device and all the output clocks should be equal to the input clock.
    In my application i use one sample clock to drive ten ad devices, all the ad devices should be synchronized, so i only need a simple clock distribute device. i know TI‘many clock devices can meet my requirement , but i have to use cdcm7005 cause in the end i may use cdcm7005-sp to replace the cdcm7005 in the radiatiion situation and only cdcm7005-sp can meet the requirement.
    Regards
    guoqing
  • 0 in reply to guoqing xu
    TI__Genius 10320 points
    Hi Guoqing,

    If this is the case, then the CDCM7005 will work. Ensure to tri-state the charge pump as the VCXO is not being used.

    Gabe
  • 0 in reply to Gabe Ayala
    Prodigy 50 points
    hi Gabe

    First,thank you very much for your help.
    Then ,can you tell me how to tri-state the charge pump ?

    Should I first float the PRI_REF and SEC_REF and REF_SEL pins or tie those pins to the gound;
    second programme(SPI) the (HOLD or RESET) pin to act as HOLD and tie this pin to ground？
    What other steps I should do to tri-state the charge pump and how to deal with the VCC_CP,normally powered or floated ?
  • 0 in reply to guoqing xu
    TI__Genius 10320 points
    Hi Guoqing,

    See Table 13 on how to set the CP to 0 uA (3-state). Unused inputs can be left floating as all 3 have 150 kOhm pull-up to VDD.

    Ensure VCC_CP is powered for proper device operation.

    Gabe
  • 0 in reply to Gabe Ayala
    Prodigy 50 points

    Hi Gabe

    thanks and what is “as all 3 have 150 kOhm  pull-up to VDD”？  : )