JAJS261B July 2007 – January 2018 DAC8881
PRODUCTION DATA.
The DAC8881 offers a force and sense output configuration for the high open-loop gain output amplifier. This feature allows the loop around the output amplifier to be closed at the load (as shown in Figure 68), thus ensuring an accurate output voltage. The output buffer VOUT and RFB pins are provided so that the output op amp buffer feedback can be connected at the load. Without a driven load, the DAC8881 output typically swings to within 15mV of the AGND and AVDD supply rails. Because of the high accuracy of these DACs, system design problems such as grounding and contact resistance become very important. A 16-bit converter with a 5 V full-scale range has a 1 LSB value of 76 μV. With a load current of 1 mA, a series wiring and connector resistance of only 80mΩ (RW2) causes a voltage drop of 80 μV. In terms of a system layout, the resistivity of a typical 1-ounce copper-clad printed circuit board is 0.5mΩ per square. For a 1mA load, a 0.25 mm wide printed circuit conductor 25 mm long results in a voltage drop of 50 μV.