Several pressure sensor manufactures promote product incorporating "dual die compensation." This compensation technique is employed for very low-pressure sensors where common mode errors cannot be compensated by any other means, for either gage or differential pressure measurements.
There are two forms of dual die compensation. One form of dual die compensation incorporates two pressure sensors but only one of the two sensors provides a pressure sensitive output. The second sensor is passive and is used solely to correct for common mode errors. The second form of dual die compensation incorporates two pressure sensors and both sensors provide a pressure sensitive signal. Both these compensation techniques are embodied in patent 6,023,978. This compensation technique applies to all common mode errors and is the only technique available to compensate for long term drift of output offset voltage.
This white paper illustrates dual die compensation methods where common mode errors are reduced in comparison to traditional methods and illustrates a reference to traditional sensor construction where common mode errors are not reduced.