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CDCE62005: LVDS Fail Safe Mode

Hiroshi Katsunaga
Mastermind 6480 points

Part Number: CDCE62005

Hello,

My customer has a question about the LVDS Fail Safe Function in CDCE62005.

[Q]

Their configuration as follows.

  * Hysteresis = Enabled

  * Mode = LVDS

  * Coupling = DC

  * Termination = External

In this case, Can it enable the fail safe function (FAILSAFE=1) ?

If it can not enable the fail safe function, why can it not enable that ? 

If you can explain it with internal circuit, then It is very helpful for me.

Best Regards,

Hiroshi Katsunaga

  • 0
    TI__Genius 16845 points
    Hi Hiroshi,

    In this case, the fail safe mode can be used. When "1" is written to R5.11, fail safe mode is enabled for LVDS, DC-coupled inputs only.

    Kind regards,
    Lane
  • 0 in reply to Lane Boyd
    Mastermind 6480 points

    Hi Lane,

    Thank you for your fast response.

    I tried it by using CDCE62005EVM.

    I used secondary reference with DC Coupled LVDS, External termination, 10MHz.

    The modified points as follows.

      * R115 = Open (LVPECL bias = No bias)

      * R116 = Open (LVPECL bias = No bias)

      * C78 = 0 ohm

      * C79 = 0 ohm

      * JP_3_6 = 2-3 (LVPECL)

      * JP_3_7 = 2_3 (LVPECL)

    I attached my configuration files.

     (a) 171208_M_TEST_Sec10Min_150Mout_Unlock.INI

     (b) 171208_M_TEST_Sec10Min_150Mout_Lock.INI

    (a) file set with FAILSAFE=1. It was not lock in this configuration.

    (b) file set with FALSAFE=0. It was lock in this configuration.

    https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/48/171208_5F00_M_5F00_TEST_5F00_Sec10Min_5F00_150Mout_5F00_Unlock.INI

    https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/48/171208_5F00_M_5F00_TEST_5F00_Sec10Min_5F00_150Mout_5F00_Lock.INI

    I think my configuration make some mistake or your answer is wrong.

    Please check it and please give me your additional comments.

    Best Regards,

    Hiroshi Katsunaga

  • 0 in reply to Hiroshi Katsunaga
    Mastermind 6480 points

    Hi Lane,

    How about the above additional questions ?

    Best Regards,

    Hiroshi Katsunaga

  • 0 in reply to Hiroshi Katsunaga
    TI__Genius 16845 points
    Hi Hiroshi,

    As we discussed offline, I was able to replicate this issue on my bench. I do not recommend setting FAILSAFE high.

    KInd regards,
    Lane
  • 0 in reply to Lane Boyd
    Mastermind 6480 points
    Hi Lane,

    Thank you for your many help.

    Best Regards,
    Hiroshi Katsunaga