Module 5 ADC.pptx r2r dac adc and other components

electronics and communication engineering subject AEC

1. 18EC42 Analog Circuits: Module 5 ADC: SAR Preethi A ECE, CMRIT

2. Analog to Digital Converter Computational Systems are Digital in nature All the information to be processed are Analog in nature Digital systems are economical, reliable and Easy to Design

3. SAR Type ADC SAR: Successive Approximation Register

4. Concept: Similar to Binary Search

5. Successive Approximation Type

6. Weights associated with each bit

7. 4 bit ADC Clk B3 B2 B1 B0 VD VA>VD Decision V0 op 2.5 1.25 0.625 0.3125 1 1 2.5 No Reset V A =2V V ref =5 Step Size =5/16= 0.3125 %Error = (2-1.875)*100/2 (0.125*100)/2=6.2% 2 1 1.25 Yes Set 1.25 3 1 1 1.875 Yes Set 1.875 4 1 1 1 2.1875 No Reset 1.875 0110

8. Problem For an 8 bit SAR based ADC with following parameters give the digital equivalent output, resolution and calculate error. Reference Voltage:5v Analog input: 2v

9. Solution

10. Advantages High Speed Better Resolution