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Minor bug in VL53L0X board

Hi there, regarding the advice for bypassing the internal regulator on the VL53L0X board, namely supplying the 2.8V directly on VDD and leaving VIN disconnected, I think you may have forgotten to mention something. Referring to the following simulation, you can see that if VIN is left disconnected, there is a 20k path between SDA and SCL which results in cross talk between the lines (when one line is driven low, the other line is also driven uncomfortably low 1.4V).

Pulling up the SDA and SCL lines to 2.8V via 10k or 5k resistors helps a bit, but the cross talk is still there and makes the “high” level on the other line uncomfortably low (2.01V for 10k and 2.25V for 5k).

Hello,

This is not an issue because when the board is powered directly from VDD, the regulator allows some current to flow in reverse from VDD to VIN, so VIN ends up at about the same voltage and the VIN pull-ups work basically as expected. If you want to be extra sure that this kind of crosstalk does not happen, you can add a direct connection between VDD and VIN yourself.

Kevin

Thanks for the answer that, Kevin. Quick follow up question: wouldn’t supplying 2.8V on both VIN and VDD switch the regulator on since the VIN pin is also connected to the EN pin on the regulator?

Yes, the regulator will be enabled, but that should be fine. It might use slightly more power, but the difference is very minor.

Kevin