S = Slope (V/A)

best fit linear

15

TMCS1101

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SBOS825A – SEPTEMBER 2019 – REVISED MAY 2020

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8 Parameter Measurement Information

8.1 Accuracy Parameters

The ideal first-order transfer function of the TMCS1101 is given by Equation 1, where the output voltage is a

linear function of input current. The accuracy of the device is quantified both by the error terms in the transfer

function parameters, as well as by nonidealities that introduce additional error terms not in the simplified linear

model. See Total Error Calculation Examples for example calculations of total error, including all device error

terms.

where

•

•

S is the ideal sensitivity of the device.

•

•

(1)

8.1.1 Sensitivity Error

Sensitivity is the proportional change in the sensor output voltage due to a change in the input conductor current.

This sensitivity is the slope of the first-order transfer function of the sensor, as shown in Figure 21. The sensitivity

of the TMCS1101 is tested and calibrated at the factory for high accuracy.

Figure 21. Sensitivity, Offset, and Nonlinearity Error

Deviation from ideal sensitivity is quantified by sensitivity error, defined as the percent variation of the best-fit

measured sensitivity from the ideal sensitivity. When specified over a temperature range, this is the worst-case

sensitivity error at any temperature within the range.

where

•

•

•

(2)

8.1.2 Offset Error and Offset Error Drift

Offset error is the deviation from the ideal output voltage with zero input current through the device. Offset error

error is a single error source, however, and must only be included once in error calculations.