This document discusses different types of digital to analog converters (DACs). It describes the binary weighted resistor type DAC where each digital level is converted to an equivalent analog voltage or current. It provides the circuit diagram of this DAC and analyzes how the output voltage is calculated based on the input binary sequence and reference voltage. Examples are given for 3-bit DACs with different input combinations. The output is shown to be a staircase waveform.

1. PRIORITY ENCODER

2. 8-to-3 Bit Priority Encoder

3. 8-to-3 Bit Priority Encoder

4. PRIORITY ENCODER NAVIGATION

5. PRIORITY ENCODER NAVIGATION…

6. INTEGRATOR CIRCUIT

7. RAMP GENERATOR OUTPUT

8. BINARY WEIGHTED RESISTOR DAC
In the weighted resistor type DAC, each digital level is converted
into an equivalent analog voltage or current.
The following figure shows the circuit diagram of the binary
weighted resistor type DAC.

9. Analysis:
Let us analyze the circuit using normal analysis concepts
used in op-amp. When the switches are closed the
respective currents are flowing through resistors as shown
in the circuit diagram above.
Since input current to the op-amp is zero, the addition
current flows through feedback resistor.
∴I=I1+I2+I3+ …………+In
The inverting terminal of op-amp is virtually at ground
potential.

10. Consider the example of 3-bit DAC.
When input binary sequence is B1 B2 B3 = 001
When input binary sequence is B1 B2 B3 = 101

11. If the reference voltage is positive i.e. + VR, then the output
voltage is positive.
Similarly for other six combinations of digital input, the analog
output voltage Vo is calculated as follows

12. The following figure shows the staircase output voltage
waveform obtained for R-2R ladder DAC (when VR is positive