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TMCS1100

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SBOS820 – SEPTEMBER 2019

Product Folder Links: TMCS1100

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Copyright © 2019, Texas Instruments Incorporated

Accuracy Parameters (continued)

Sensitivity error drift is the worst-case change in sensitivity error per degree Celsius change in ambient

temperature. This parameter is reported in ppm/°C. To convert sensitivity error drift to a percentage for a given

change in temperature, multiply the drift by the change in temperature and convert to percentage, as in

Equation 3.

where

•

•

ΔT is the temperature range from 25°C.

(3)

8.1.2 Offset Error and Drift

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

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

The output voltage offset error of the TMCS1100 is the error in the zero current output voltage from the VREF

pin voltage.

where

•

(4)

The total offset error includes multiple individual error sources: errors from the VREF pin potential to VOUT, the

magnetic offset of the Hall sensor, and any offset voltage errors of the signal chain.

The input referred (RTI) offset error is the output voltage offset error divided by the sensitivity of the device,

shown in Equation 5. Refer the offset error to the input of the device to allow for easier total error calculations

and direct comparison to input current levels. However the calculations are done, the error sources quantified by

(5)

Offset error specifications are defined at both room temperature and across the full temperature range. Offset

error specified over a temperature range is the worst-case sensitivity error at any temperature within the range,

and must not be considered as additive to room temperature offset error. Offset error drift is the worst-case rate

of change in a device offset across the temperature spectrum, and is used to calculate maximum offset error

across an arbitrary temperature range in the same manner as sensitivity drift, and as described in the Total Error

Calculation Examples section.

8.1.3 Nonlinearity Error

Nonlinearity is the deviation of the output voltage from a linear relationship to the input current. Nonlinearity

voltage, as shown in Figure 1, is the maximum voltage deviation from the best-fit line based on measured

parameters, calculated by Equation 6.

where

•

•

•

•

(6)

(7)