Datasheet

DAC0830, DAC0832

www.ti.com

SNAS534B –MAY 1999–REVISED MARCH 2013

Input Code IDEAL V

OUT

MSB LSB +V

REF

−V

REF

1 1 1 1 1 1 1 1

1 1 0 0 0 0 0 0

1 0 0 0 0 0 0 0

0 1 1 1 1 1 1 1

0 0 1 1 1 1 1 1

0 0 0 0 0 0 0 0

Full-Scale Adjustment

In the case where the matching of R

to the R value of the R-2R ladder (typically ±0.2%) is insufficient for full-

scale accuracy in a particular application, the V

REF

voltage can be adjusted or an external resistor and

potentiometer can be added as shown in Figure 21 to provide a full-scale adjustment.

The temperature coefficients of the resistors used for this adjustment are of an important concern. To prevent

degradation of the gain error temperature coefficient by the external resistors, their temperature coefficients

ideally would have to match that of the internal DAC resistors, which is a highly impractical constraint. For the

values shown in Figure 21, if the resistor and the potentiometer each had a temperature coefficient of ±100

ppm/°C maximum, the overall gain error temperature coefficent would be degraded a maximum of 0.0025%/°C

for an adjustment pot setting of less than 3% of R

Using the DAC0830 in a Voltage Switching Configuration

The R-2R ladder can also be operated as a voltage switching network. In this mode the ladder is used in an

inverted manner from the standard current switching configuration. The reference voltage is connected to one of

the current output terminals (I

OUT1

for true binary digital control, I

OUT2

is for complementary binary) and the output

voltage is taken from the normal V

REF

pin. The converter output is now a voltage in the range from 0V to 255/256

REF

as a function of the applied digital code as shown in Figure 22.

Figure 21. Adding Full-Scale Adjustment

Figure 22. Voltage Mode Switching

Product Folder Links: DAC0830 DAC0832