TMP411-Q1: How to calculates a specific value of Rs .

Jay wang

Intellectual 1501 points

Part Number: TMP411-Q1
Other Parts Discussed in Thread: TMP411

Hi Sensor Team,

From datasheet, I understand that Rs and Cdiff can minimize noise found in the end equipment.

Is there a formula or way to calculates a specific value?

Thank you very much.

over 1 year ago

+1 Josh Wyatt over 1 year ago

TI__Guru* 91086 points

Dear Jay -

In this case, resistance is not desired, hence the reason for the series resistance cancellation feature built in. The representation of Rs is indicating whatever resistance is presented by the PCB traces or wires, and is not advising to put resistance there. You can refer to Figures 4, 5 and 6 in the datasheet to see the negative impact of increasing values of R and C on the temperature accuracy.

Equation 14 on page 11 of this application note can help you solve for Rs in the circuit, however note that the TMP411 uses four currents vs three in the example presented there.

https://www.ti.com/lit/an/sboa173a/sboa173a.pdf