Dac Basics - Agilent Technologies 93000 SOC Series Training Manual

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DAC Basics

A DAC converts a digital value, which is applied via n data lines,
into an analog voltage.
DAC Block Diagram
Example of a 3-bit DAC
Vref
a
0
digital code
Rf
Vo =
R
DAC Block Diagram
DAC Transfer Curve
Linear DACs have a transfer characteristic as shown below:
Discrete Analog
Output Voltage
Digital input code
Ideal DAC
DAC Transfer Curves
Real DACs show minor or major non-linear deviations.
Lesson 1 – The Training DAC
2R 8R
4R
Rf
a a
1 2
a a
a
1 2
0
( + + )
Vref
8
2 4
Discrete Analog
Output Voltage
Digital input code
Non-Ideal DAC
Vo
157