Internal Bandgap Reference Sensitivity to Board Level Thermal Gradient Shifts
Board level thermal gradients shift internal bandgap voltages by inducing transistor temperature differentials and piezoresistive package stress.
ADC Full Scale Error
Conversion Deviation
An analog deviation represents the difference between the ideal maximum analog input voltage and the actual voltage that triggers the maximum digital output code. When a converter exhibits ADC full scale error, the transfer function deviates from its intended path at the highest point of the range. This discrepancy is expressed in least significant bits or as a percentage of the full-scale range.
The parameter excludes the influence of offset errors, focusing solely on the gain deviation and internal reference inaccuracies.
Transfer Discrepancy
Quantification of this phenomenon occurs after zero-scale errors are nullified. The ADC full scale error represents the compounding of the gain error and the voltage reference drift. This shift alters the slope of the conversion line, which creates a non-linear behavior across the upper operating region.
Reference Stability
An internal bandgap reference often dominates the drift seen in precision data acquisition systems. Thermal variations in the reference voltage scale directly with the input level, reaching their peak influence at the limits of the converter range.
Digital Calibration
Mitigation of this error relies on multi-point calibration routines. Systems correct the slope digitally by multiplying the raw output by a correction factor derived from a known precision voltage.