Precision, Bipolar, Configuration for the AD5547/AD5557 DAC
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Circuit Function & Benefits

This circuit provides precision, bipolar data conversion using the AD5547/AD5557 current output DAC with the ADR01 precision reference and AD8512 operational amplifier (op amp). This circuit provides accurate, low noise, high speed output voltage capability and is well suited for process control, automatic test equipment, and digital calibration applications.

Figure 1: 4-Quadrant Multiplying Mode, VOUT = –VREF to +VREF

Circuit Description


This circuit uses the ADR01, which is a highly accuracy, high stability, 10 V precision voltage reference. As voltage reference temperature coefficient and long-term drift are primary considerations for applications requiring high precision conversion, this device is an ideal candidate.

An op amp is used in the current-to-voltage (I-V) stage of this circuit. An op amp’s bias current and offset voltage are both important selection criteria for use with precision current output DACs. Therefore, this circuit employs the AD8512 op amp, which has ultralow offset voltage (80 μV typical for B-grade device) and bias current (25 pA typical). C9 is a compensation capacitor. The value of C9 for this application is 2.2 pF, which is optimized to compensate for the external output capacitance of the DAC.



The input bias current of an op amp also generates an offset at the voltage output as a result of the bias current flowing through the feedback resistor, RFB. In the case of the AD8512, the input bias current is only 25 pA typical, which flowing through the RFB resistor (10 kΩ typical) produces an error of only 0.25 μV.



where D = 0 to 65535 for 16-bit DAC (D is the decimal equivalent of the input code). VOUT can be calculated for the AD5557 using the equation


where D = 0 to 16383 for 14-bit DAC (D is the decimal equivalent of the input code).

Common Variations

The AD8605 is another excellent op amp candidate for the I-V conversion circuit. It also has a low offset voltage and low bias current. The ADR02 and ADR03 are other low noise references available from the same reference family as the ADR01. Other low noise references that would be suitable are the ADR441 and ADR445 products. The size of the reference input voltage is restricted by the rail-to-rail voltage of the op amp selected.


Sample Products





Available Product
Models to Sample

ADR441 Ultralow Noise, LDO XFET® 2.5V Voltage Reference w/Current Sink and Source










AD8512 Low Noise, Low Input Bias Current, Wide Bandwidth Precision JFET Dual Op Amp





ADR01 Ultracompact, Precision 10.0 V Voltage Reference