Abstract: Offset calibration for an analog front-end system is provided. The analog front-end system includes a variable-gain amplifier, and the calibration mitigates an offset error of the variable-gain amplifier. Calibration is based on a difference-based estimation technique combined with digital iteration. Difference-based estimation includes measuring different digital output signals from an analog-to-digital converter for different respective gains of the variable-gain amplifier. The digital iteration is utilized to estimate offsets values which converge a digital output difference to a target of zero volts.

Abstract: In an embodiment, a digital-to-analog converter (DAC) converts an input digital signal into an output analog signal, and includes first and second segments, a combiner, and a controller. The first segment includes a first number of first elements that are configured to generate a first analog signal in response to a first portion of the digital signal, and the second segment includes a second number of second elements that are configured to generate a second analog signal in response to a second portion of the digital signal. The combiner is configured to combine the first analog signal and the second analog signal to generate the output analog signal, and the controller is configured to deactivate one of the first elements and to activate one of the second elements in place of the deactivated first element. For example, such a segmented DAC may be suitable for use in a sigma-delta ADC.