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TMP61-Q1: My customer wants to set Vbais=3.3V(approx..) by changing Rbias.

Part Number: TMP61-Q1

Dear Experts,

This is Koki Tsushima.

My customer wants to set Vbais=3.3V(approx..)  by changing Rbias.

I understood that detail calc. or simulation is needed if user want to use non- 10kΩ Rbias by this E2E.

https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/1109068/tmp61-q1-how-to-get-proper-formula-when-rbias-is-not-10k?tisearch=e2e-sitesearch&keymatch=TMP61%2C%2010k#

If it can be calc by customer, is it OK to adopt non-10kΩ which come true Vbias=3.3V (approx.)?

Is there limitation of value of Rbias (min / max)?

Or because non-10kΩ resistance "impact to temperature relationship and may cause temperature errors outside of the specified tolerances in the datasheet".

should it not be recommended to use?

Thank you,

Koki Tsushima

• Hi Tsushima-san,

As mentioned in the previous post you linked, we recommend using a 10 kΩ Rbias with the TMP61-Q1. This allows the 4th order polynomial in the Thermistor Design Tool to be used to convert voltage to temperature.

If the customer plans on using an Rbias value different from 10 kΩ, this will change the current through the device and they will need to generate a new 4th order polynomial. This app note describes how to create a fourth order polynomial: https://www.ti.com/lit/an/sboa537/sboa537.pdf.

You can also use the PSPICE model of the TMP61 to help with simulation of the new circuit.

As far as limitations on the value of Rbias, you want to make sure that the current through the device doesn't exceed the max spec in the datasheet.

Best regards,

Jesse