Datasheet

TMC4671 Datasheet • IC Version V1.3 | Document Revision V2.00 • 2020-Apr-17
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Figure 16: Input Voltage Ranges of internal Delta Sigma ADC Channels)
Figure 16 illustrates typical relation between input voltage and corresponding raw ADC output. For
differential operation the input range between 25% and 75% corresponds to voltage values between 1.25V
to 3.75V. This is the recommended operation area of the ADC. Below 25% and above 75% the ADC shows
significant non-linearity due to the Delta Sigma measurement principle.
In single ended operation the recommended input range starts at 0V and ends at 1.25V. Measurement
below GND might be distorted and is not recommended.
Info
Due to manufacturing tolerances calibration of offset and amplitude is always
recommended. Please also consider stability of the reference voltage.
4.4.12 External Delta Sigma ADCs
The delta sigma front-end of the ADC engine supports external delta sigma modulators to enable isolated
delta sigma modulators for the TMC4671. Additionally, the delta sigma front-end supports low-cost
comparators together with two resistors and one capacitor (R-C-R-CMP) forming first order delta sigma
modulators, as generic analog front-end for pure digital variants of the TMC4671 core.
4.4.13 ADC Group A and ADC Group B
ADC channels of the TMC4671 are grouped into two groups, to enable different sample rates for two groups
of analog signals if needed. Running both ADC groups with same sampling frequency is recommended
for almost all applications. It might be necessary to run its ADC channels of analog encoder with a much
higher frequency than the ADC channels for current measurement in case of using a high resolution analog
encoder.
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