1. Why Data Conversion? Real world is analog Mostly, communication and computation is digital Need a component to convert analog signals to digital (ADC) and convert the processed digital signal back to analog (DAC)

2. Types of Data Converters Niquist rate data converters Serial Successive approximation Flash Oversampling (Sigma-Delta) Power consumption Area consumption Operating speed Conversion time (delay) Error (Linearity) Noise performance And many more…. How is a data converter characterized ???

5. Ideal DAC/ADC characteristics DAC ADC

6. Integral Non-Linearity Error INL: Deviation of the code transition from its ideal location

7. Differential Non-Linearity Error DNL: Deviation of the code width from 1 LSB

9. Full Scale Error Full scale error: Difference between the actual value that triggers the transition to full-scale and the ideal analog full-scale transition value

10. Gain Error Gain error: Difference between the slope of an actual transfer function matches the slope of the ideal transfer function

11. Noise Performance SNR (signal to noise ratio): Ratio of the fundamental signal to the noise spectrum. THD (total harmonic distortion): Ratio of the fundamental signal to the noise spectrum. SFDR (spurious free dynamic range): Ratio of the fundamental signal and the highest spurious in the spectrum SINAD (Signal-to-Noise And Distortion): combination of SNR and THD SINAD = 20 * log ([Fundamental] / SQRT (SUM (SQR([Noise + Harmonics])))) ENOB (Effective Number of Bits): (SINAD – 1.76) / 6.02

12. More Information http://www.maxim-ic.com/appnotes.cfm/appnote_number/641 http://inst.eecs.berkeley.edu/~ee247/fa05/lectures/L12_2_f05.pdf http://inst.eecs.berkeley.edu/~ee247/fa05/lectures/L11b_f05.pdf Preliminary Slightly Advanced