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Visitor
August 19, 2026
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RHFLVDS31A Unused I/O pins

  • August 19, 2026
  • 2 replies
  • 24 views

Hello,

Im using the RHFLVDS31A  and I have some unused I/O pins. Should I terminate them or should I leave them floating? I saw that there is an internal pull up for Cold Sparing so I didn’t want to impact that.

Best answer by Peter BENSCH

Welcome ​@Lobert124, to the community!

I am not a Rad-Hard specialist; however, it is always advisable to terminate unused digital inputs if they are not already terminated with internal pulls, as in the case of G and /G. Whether the outputs need to be terminated will probably emerge from your application’s requirements specification.

Cold sparing has nothing to do with pull, but rather, as the datasheet states, are "buffers to ensure they are in high impedance when VCC is tied to GND". 

Hope that helps?

Regards
/Peter

2 replies

Peter BENSCH
Peter BENSCHBest answer
ST Technical Moderator
August 19, 2026

Welcome ​@Lobert124, to the community!

I am not a Rad-Hard specialist; however, it is always advisable to terminate unused digital inputs if they are not already terminated with internal pulls, as in the case of G and /G. Whether the outputs need to be terminated will probably emerge from your application’s requirements specification.

Cold sparing has nothing to do with pull, but rather, as the datasheet states, are "buffers to ensure they are in high impedance when VCC is tied to GND". 

Hope that helps?

Regards
/Peter

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Lobert124Author
Visitor
August 19, 2026

OK sounds good Peter, I just wanted to double check in case there were some internal ESD or pull up that wasn’t mentioned.