ZHCSHP3 February 2018 DAC8771
PRODUCTION DATA.
There are three possible hardware power supply configurations for the DAC8771: the internal DC/DC provides both positive and negative supply voltages, the internal DC/DC provides only one of the supply voltages with an external supply provided on the other, or the internal DC/DC is not used at all and external supply voltages are provided for both positive and negative supply voltages. Simple illustrations for each case are as follows.
Figure 129. DAC8771 With Dual Supplies from Internal DC/DC
Figure 130 illustrates using a single supply from the DAC8771 internal DC/DC and the other supply from an external source. In this example the VNEG_IN supply is the input being supplied by an external supply, or ground for unipolar output spans. A similar scheme could be used if VPOS_IN was supplied by an external supply and VNEG_IN was supplied by the internal DC/DC.
Figure 130. DAC8771 With Single Supply from Internal DC/DC
The scheme in Figure 131 should be used if the internal DC/DC is not used at all and external supplies are selected for VPOS_IN and VNEG_IN. When using external supplies for VPOS_IN it is important that VPOS_IN, PVDD, and AVDD nodes are tied to the same voltage potential with the same ramp-rate
Figure 131. DAC8771 With External Supplies