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VL53L0X. Why does a 1kOhm resistor stabilize the sensor after resetting with XSHUT?

Andrey_17112021
Associate

The Datasheet describes that if the sensor is powered and the XSHUT is active, then the sensor is in HW Standby mode. It seems that in my case, the sensor does not always work correctly after exiting XSHUT mode. It can give errors RangeStatus = 2, RangeStatus = 4, and RangeStatus = 255. With a certain probability, after resetting the sensor using XSHUT, the sensor starts working correctly.

I use Dupont 20 cm wires, it looks like a 1 kOhm resistor between the XSHUT pin and the host stabilizes the sensor, that is, after resetting the sensor with XSHUT, it works stably without errors. This resistor is not on the circuit from the Datasheet, but it is in a number of circuits from the Internet. Is this resistor necessary and how can it affect the operation of the sensor?

Thank you.

1 REPLY 1
John E KVAM
ST Employee

I really don't know, but I have a guess. The XShut line is subject to noise. Should the line go low due to a glitch, the sensor will start to go down, but if the line comes up quick enough, the sensor gets left in a confused state.

I'm going to guess your resistor is somehow eliminating some noise.

I generally suggest a good strong pull-up on this line an maybe a decoupling cap.

  • john

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