A Low-Noise Low-Drift Transducer ADC

An ADC is described that achieves the very high resolution and low offset-and gain-drift required in converting the low-level output from a load-cell transducer. The ADC comprises a tare DAC, a PGA and a sigma-delta converter. The filter in the converter has a special mode to enable it to rapidly track changes in the transducer output. The ADC is also capable of accurately calibrating it's gain in spite of the very small full-scale of 10mV.