R 2r Ladder Circuit Diagram

Study of r2r 4 bit and 8 bit dac circuit using multisim technology raghavendra.

R 2r ladder circuit diagram. Well it is just a cleverly arranged set of resistors that gives you the unique action of turning binary signals into an analogue output voltage. The switch positions decides the binary word i e. This is another advantage of the r 2r dac. A 4 bit r 2r network the r 2r resistor ladder network directly converts a parallel digital symbol word into an analog voltage.

An r 2r ladder is a simple and inexpensive way to perform digital to analog conversion using repetitive arrangements. The circuit diagram of a 3 bit r 2r ladder dac when binary input b 2 b 1 b 0 100 applied to it is shown in the following figure in the above circuit there exists series and parallel combinations of resistors to the left of point a with respect to ground. The r 2r ladder is made up of divide by two stages so that when you apply a logic voltage we ll call the levels vcc and gnd to the top rung of the ladder you get vcc 2 or gnd. The number of digits per binary word is assumed to be two i e.

Here only two values of resistors are required i e. Now see the practical circuit arrangement of 4 bit r 2r ladder d a converter using op amp. A digital to analog converter includes an input circuit 9 producing a plurality of corresponding switch control signals 25 in response to a digital input signal d in and a resistive ladder network 10a including an r 2r msb ladder section 2 including a plurality of r resistors 17 and a plurality of 2r resistors 5 and an r 2r lsb ladder section 3 including a plurality of r. What it is and why you need one so what is an r 2r ladder.

B1 b0 the typical value of feedback resistor is rf 2r. The inverting input terminal of the op amp work as a summing amplifier for the ladder inputs. An r 2r ladder dac. A simplified representation of an r 2r ladder digital to analog converter is shown below.

Let the binary value b3 b2 b1 b0 if b3 1 b2 b1 b0 0 then the circuit is shown in the figure below it is a simplified form of the above dac circuit. So we can get out put voltage by bellow equation. It works by the principle of superposition where switching on binary inputs adds more voltage at the output. Each digital input b0 b1 etc adds its own weighted contribution to the analog output.

In order to achieve high level accuracy we have chosen the resistor values as r and 2r. The circuit is expandable to any number of bits simply by adding one resistor of each value for each bit. R 2r ladder digital to analog converter dac the above figure shows the 4 bit r 2r ladder dac. Uttara kumari3 1 2 3 r.

The following circuit diagram shows the basic 2 bit r 2r ladder dac circuit using op amp. From digital fundamentals 7 th edition.