DAC Output Amplifier
Shown is a typical hook-up for a current output DAC with complimentary current outputs. Although the DAC itself is shown operating from a single supply, the output amplifier must be powered from ± voltage supplies, since the voltage output will be the opposite polarity to VREF. RFB is an internal resistor matched to the DAC resistor network and is normally connected in feedback with the amplifier. To increase the output voltage swing, a 2nd resistor (R2) may be added in series with RFB. Conversely, to lower the output swing a resistor (R1) is placed in series with VREF to limit the full-scale current. Capacitor C1 is added to compensate for the internal switch capacitance.
