SBOS825D September 2019 – July 2021 TMCS1101
Offset error is the deviation from the ideal output voltage with zero input current through the device. Offset error can be referred to the output as a voltage error VOE or referred to the input as a current offset error IOS. Offset error is a single error source, however, and must only be included once in error calculations.
The output voltage offset error of the TMCS1101 is the deviation of the measured VOUT with zero input current from the ideal value of the zero current output voltage. This ideal voltage is either 10% of VS for unidirectional devices (AxU) or 50% of VS for bidirectional devices (AxB), as shown in Equation 3 and Equation 4, respectively.
The offset error includes errors in the internal reference, 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. No matter how the calculations are done, the error sources quantified by VOE and IOS are the same, and should only be included once for error calculations.
Offset error drift is the change in the input-referred offset error per degree Celsius change in ambient temperature. This parameter is reported in µA/°C. To convert offset drift to an absolute offset for a given change in temperature, multiply the drift by the change in temperature and convert to percentage, as in Equation 6.