Split or Single Supply Operation, Bidirectional Output into A/D

In this circuit, split supply operation is used on both the LT1787 and LT1404 to provide a symmetric bidirectional measurement. In the single-supply case, where the LT1787 pin 6 is driven by VREF, the bidirectional measurement range is slightly asymmetric due to VREF being somewhat greater than mid-span of the ADC input range.