Overal error

AN4369

10/14

DocID025335 Rev 1

6

Overal error

This application note summarizes the error terms on the gain and Vout by adding serial

resistors on the Vn and Vp pins. It does not take into account the output voltage accuracy

described in the TSC datasheets because this parameter is always applicable (with or

without serial resistances on the inputs).

The following example (for the TSC103) considers the overall error i.e. all error due to

process variation and the temperature coefficient. The mismatch for Vsense = 50 mV.

Vsense = 50 mV

Internal gain (G) = 20 but, with the addition of Rsi, G = 500 Ω and theoretical gain is =

18.18 V/V)

Temperature = 125 °C

Process variation = 20 %

Rsi precision = ±1 %

Temperature coefficient of internal resistance = 0.7 %/°C

Temperature coefficient of external resistance = 100 ppm/°C

The gain error due to the temperature coefficient is:

So, εTC = 6.27 %

The gain error due to process variation is:

So, εPV = 1.87 %

The total gain error is:

So,

εG = 8.14 %