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

over 6 years ago

0 Lane Boyd over 6 years ago

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 Hiroshi Katsunaga over 6 years ago 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.

171208_M_TEST_Sec10Min_150Mout_Unlock.INI

171208_M_TEST_Sec10Min_150Mout_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 Hiroshi Katsunaga over 6 years ago in reply to Hiroshi Katsunaga

Mastermind 6480 points

Hi Lane,

How about the above additional questions ?

Best Regards,

Hiroshi Katsunaga

0 Lane Boyd over 6 years ago 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 Hiroshi Katsunaga over 6 years ago in reply to Lane Boyd

Mastermind 6480 points

Hi Lane,

Thank you for your many help.

Best Regards,
Hiroshi Katsunaga

Clock & timing

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CDCE62005: LVDS Fail Safe Mode