TMS570LS3137: Kelvin_GND pin 19 question

Hi Chuck,
Thanks for the response! Can you point me to where in the documentation it says this? The only place I found in the datasheet is note B for figure 6-4a (crystal case) that says Kelvin_GND should not be connected to any other GND.
Thanks,
Scott

Hi Scott,

Unfortunately, I cannot. I do not believe that we have this type of recommendation listed anywhere because it is not a typical use case that we considered when generating the documentation.

Hi Chuck,

You mentioned that what I described is not a typical use case. Just to clarify, instead of using option (A) with a crystal, we are using option (B) of the datasheet figure 6-4: External Clock Signal (toggling 0V to 3.3V). Searching the E2E forum, I found others with the same question regarding KELVIN_GND and option B of figure 6.4. So it appears it is a typical use case and warrants a document update. In the meantime, for option B we will connect KELVIN_GND to board ground as you recommend.

Thanks for your help!

Scott

Hello Scott,

The (b) configuration is usually used for bench related activities, but can certainly be configured in this way on your board. By far, option (a) is typical and option (b) use is more isolated/less typical. That not withstanding, I do believe it is a valid configuration and have submitted document feedback to add clarification of hook up of Kelvin GND in the event option (b) is selected for a design/application use condition.

In the end, I don't believe this to be a critical point of contention. I think you will see success regardless if you tie it to GND or leave it as a NC. The recommendation to tie to GND simply is a more deterministic state of the pin than leaving it floating/unconnected which is why I made the recommendation.