MLX90365 - Contactless Rotary position sensor problems

[cmcraeslo]

Hey guys.

I'm having issues with MLX90365 sensor not working as I imagined

I've attached the schematics I'm using. It's pretty straight forward and basically a copy-paste from the datasheet. What I want is to fix this below the magnet and when magnet rotates, get 0.5 - 4.5V depending on the orientation. What I get is a constant 2.4V on the output, regardless of the orientation or position, or even change if magnet is present or not. I tried two different IC, thinking one could be damaged, but I get same result. What am I missing ?

Is there some special magnet needed for this?

Part datasheet:
https://www.melexis.com/-/media/files/documents/datasheets/mlx90365-datasheet-melexis.pdf

I'd really appreciate any pointers.

Thanks!

[saike]

If you are using a round magnet, it needs to be polarised the correct way
https://www.kjmagnetics.com/proddetail.asp?prod=D42DIA

[cmcraeslo]

Thank you for pointing this out. I ordered different magnets for my project.
In the mean time, I tried positioning the magnet horizontally, but it's still the same. Output is always 1/2 of the supply voltage. If magnet is not present, voltage should be out of range probably?

[cmcraeslo]

Hey. Still struggling with this.. does anyone have any other idea what to do ? I'm getting half of the VCC voltage on the output, no matter what I do.

[RABeng224]

Looks like you grounded the output. The  other side of the 20ohm resistor is connected to ground if I’m reading your schematic right.

[BrianHG]

According to the data sheet, pin 4 should be tied to GND, even though in the pin-list, it says 'Not Used'.

Change C2 to 4.7nf.  Your device may be configured in PWM mode?

How have you asked Melexis to configure it?
Or, have you programmed it?

[cmcraeslo]

Hey.

When I removed the 100nF, I got what looks to be a PWM signal. Signal is still not changing with the magnet, but using the rc combination above I cut the frequency so it's pretty obvious that I got half of the voltage on the output. I have not configured this chip, from the datasheet, it looks like default mode is analog, not PWM (page 20 of the datasheet states that out mode 1 is default)