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I am trying to identify a Hall-sensor located on a keyboard. There is one of these sensors underneath every key. One of them are broken and needs replacing. However, I cannot identify the component.

The markings read 95B2h

It's a SOT-23 (or perhaps a slightly wider SOT-23W) package.

It appears to be an analog output as confirmed by oscilloscope (each sensor is connected to a Texas Instruments CD74HC4067 analog multiplexer.) The sensor is uni-polar as testing with a magnet only triggers the sensor from one direction. The supply voltage is 4V. The output voltage varies between 0-2V depending on key position.

Here is a picture of the component (this one isn't broken): enter image description here

This is the pinout: enter image description here

Here is a scope capture showing the supply voltage (yellow) and the output (blue) when the key is slightly depressed. My ground lead was less than optimally placed. enter image description here

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  • \$\begingroup\$ The supply voltage goes as low as 1.4V on some of the sensors. \$\endgroup\$
    – wronex
    Commented Dec 23, 2022 at 15:50
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    \$\begingroup\$ Are you sure it's an analogue output - did you confirm this? Just because it goes into analogue multiplexor can't mean it's not a digital output. \$\endgroup\$
    – Andy aka
    Commented Dec 23, 2022 at 15:54
  • \$\begingroup\$ Good point @Andyaka. I hooked up a scope. The signal is indeed PWM at 220Hz. I've edited the question to reflect this. \$\endgroup\$
    – wronex
    Commented Dec 23, 2022 at 16:28
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    \$\begingroup\$ is the supply voltage DC? \$\endgroup\$
    – jsotola
    Commented Dec 23, 2022 at 16:54
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    \$\begingroup\$ Might you swap it for one on a key you don't use much (e.g. PrtScr) while you're looking for a replacement? If you had mentioned the manufacturer of the keyboard, maybe someone would have been able to instantly reply with a reference to the actual part. There are reddit keyboard enthusiasts who know the answer ;) Have you tried resoldering it just in case the problem is only a faulty solder joint? \$\endgroup\$ Commented Dec 23, 2022 at 19:48

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If your measurements are correct, it means that Wooting might be using custom analog-output, hall-effect sensors. Out of the many analog-output, hall-effect sensors I’ve looked at, only one has been unipolar, and none output 0V.

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  • \$\begingroup\$ The DRV5056 has a device marking of 56A1Z, while the IC in question has a marking of 95B2h. \$\endgroup\$
    – Velvet
    Commented Apr 18, 2023 at 6:02

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