AN4369

Temperature coefficient error

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Temperature coefficient error

When series resistors Rs1 and Rs2 (Rsi) are inserted into the application, the output

voltage equation (see Section 2: "Internal resistances") is changed. It becomes critical to

determine the impact of these resistors on accuracy. The tempe

rature coefficient, TCβ, is

different from the temperature coefficient of the internal resistance, TCα, because the

external resistors are likely made of different material to the internal ones. In this case, the

gain is expressed as follows:

And so, due to the different temperature coefficients, gain error (%) is represented by:

Example (see also Figure 3):

R1 = 5 kΩ

R3 = 100 kΩ

TCα = 0.7 %/°C (typical value considered for TSC series)

TCβ = 100 ppm/°C

R3

R1

100 ∗