## What is R-2R digital to analog converter?

A 4-bit R-2R digital-to-analogue converter is constructed to control the speed of a small DC motor using the output from a digital logic circuit. If the logic circuit uses 10 volt CMOS devices, calculate the analogue output voltage from the DAC when the input code is hexadecimal number “B”.

**Why is R-2R ladder DAC a better choice?**

Advantages of R/2R ladder DACs: 1) Easier to build accurately as only two precision metal film resistors are required. 2) Number of bits can be expanded by adding more sections of same R/2R values. 3) In inverted R/2R ladder DAC, node voltages remain constant with changing input binary words.

**What is the advantage of R-2R digital to analog converter over weighted resistor type digital to analog converter?**

The R-2R Ladder DAC overcomes the disadvantages of a binary weighted resistor DAC. As the name suggests, R-2R Ladder DAC produces an analog output, which is almost equal to the digital (binary) input by using a R-2R ladder network in the inverting adder circuit.

### Why R-2R ladder digital to analog converter is preferable than binary weighted digital to analog converter?

**How do you find the output voltage from R to 2R ladder?**

Equation (2) can be used to calculate the full-scale output of an R/2R ladder of N bits. An R/2R ladder of 4 bits would have a full-scale output voltage of 1/2 +1/4 + 1/8 + 1/16 = 15Vr/16 or 0.9375 volts (if Vr=1 volt) while a 10 bit R/2R ladder would have a full-scale output voltage of 0.99902 (if Vr=1 volt).

**Why R 2R ladder digital to analog converter is preferable than binary weighted digital to analog converter?**

## What is the disadvantage of R-2R ladder?

Disadvantages: This type requires large range of resistors with necessary high precision for low resistors. Requires low switch resistances in transistors.

**What is the advantage of R 2R ladder D A converters over those that use binary weighted resistors?**

Advantages: Only two resistor values are used in R-2R ladder type. It does not need as precision resistors as Binary weighted DACs. It is cheap and easy to manufacture.