k32W temperature sensor instable

[MVWare]

We now have problems with two issues with K32W041:

1. Temperature sensor instability

Temperature sensor instability

The temperature sensor is unstable, it seems to ripple just like we measure on Vbat. More than 15 bits

We need extra information to reduce this ripple.

1. What type of temperature sensor sensor is used?
2. How is this measurement circuit designed?
3. Is there a relation to Vbat that causes the ripple?

[sofiaurueta]

Hello,

Hope you are doing well.

The K32W061/041 provides a linear temperature sensor which has an output internally connected to the ADC channel 7 for temperature monitoring.

Full information on using it is described in the Chapter 28 “Temperature Sensor” of the

UM11323 K32W061/K32W041 User Manual.

The ADC supports input multiplexing across up to 8 channels, including 6 external output, one temperature sensor and one for VBAT monitoring. The temperature sensor is connected to ADC channel 7 and the supply monitor (which monitors VBAT) is connected to ADC channel 6.

Any potential interaction between the temperature sensor and VBAT channels will depend on how the ADC is configured and other factors of custom design.

I would recommend checking this community post: The best way to build a PCB the first time right with K32W061, QN9090 or JN5189

Best Regards,

Sofia.

[MVWare]

Hi Sofia,  thanks for your response.

The manual does not explain any thing about the behavior of the internal temperature sensor.
We notice a strong dependancy on Vbat for the temperatue sensor...  
That is not mentioned!   
Detaild information about the internal temperature sensor is needed to fix our problems.

Answeres to the questions in the first post will help to fix the problems

[sofiaurueta]

Hello,

I apologize for the inconveniences this might cause you, the information available on the internal temperature sensor is the one included in the User Manual Chapter 28.

If this does not meet with your requirements, I would recommend using an external sensor.

Best Regards,

Ana Sofia.