Basic Op-Amp Circuits Application: D/A Conversion

Functions of D/A converter To convert digital signal to analog signal For example, changing digital music data to proper audio signal to the speaker/

Methods used by D/A converter Scaling Adder Using a scaling adder with input resistor values that represent the binary weight of the digital input code It is not most widely used method, it serves to illustrate how a scaling adder can be applied.

R/R2 Ladder Method A most commonly wide used This method doesn’t uses scaling adder

Binary-weighted resistor DAC

Continued. The lowest-value resistor R correspond to the highest weighted binary input. All of the other resistor are multiples of R and correspond to the binary weights.

Summing amplifier configuration FIGURE 13–21 Summing amplifier with n inputs.

FIGURE 13–24

FIGURE 13–26 A scaling adder as a four-digit digital-to-analog converter (DAC).

FIGURE 13–27

FIGURE 13–28

FIGURE 13–29 An R/2R ladder DAC.

FIGURE 13–30 Analysis of the R/2R ladder DAC.